Physical Review B

We have studied a three-unit-cell-thick YBa₂Cu₃O_7−δ (YBCO) superconducting film grown on a slightly vicinal SrTiO₃ substrate that was polished from the (001) plane by a small miscut angle (less than 0.5° ). This produced, on its surface, a linear array of single-unit-cell-high steps with a ...

We examine the appearance of a spontaneous bulk spin current in a triplet superconductor in contact with a metallic ferromagnet. The spin current results from the spin flip of Cooper pairs upon reflection from the interface with the ferromagnet, and is shown to display strong similarities to the spo...

We describe two different nuclear quadrupole resonance (NQR) based techniques, designed to measure the local asymmetry of the internal electric field gradient η and the tilt angle α of the main NQR principal axis ẑ from the crystallographic axis ĉ . These techniques use the dependence o...

The magnetic field dependence of the thermal conductivity κ of a HoNi₂B₂C single crystal (parallel to [110]; 2lt;T/Klt;10  ; μ₀H≤0.4 T ) is reported. It exhibits a characteristic change in the slope of κ(T) at significantly lower temperatures (or lower fields) than the resistively...

We have used first-principles calculations to study the structural, electronic, and thermodynamic properties of the three known forms of Rh-S chalcogenides: Rh₂S₃ , Rh₃S₄ , and Rh₁₇S₁₅ . Only the first of these materials of interest for catalysis had been studied previously within this approach. ...

The iron carbide Fe₇C₃ exhibits two types of basic crystal structures, an orthorhombic (o-) form and a hexagonal (h-) one. First-principles calculations have been performed for the basic Fe₇C₃ forms and for the related θ-Fe₃C cementite phase. Accurate total-energy calculations show that t...

Migration of charged point defects triggered by the local random depolarization field is shown to plausibly explain aging of poled ferroelectric ceramics providing reasonable time and acceptor concentration dependences of the emerging internal bias field. The theory is based on the evaluation of the...

In this paper, we report results for the wave packet dynamics in a class of quasiperiodic chains consisting of two types of weakly coupled clusters. The dynamics are studied by means of the return probability and the mean-square displacement. The wave packets show anomalous diffusion in a stepwise p...

We study the effects of particle size dispersion on the absorption spectrum of nonfractal random gas of particles and fractal cluster-cluster aggregates. We use the coupled-dipole equations to describe the interaction of particles with the external electromagnetic wave. We express the absorption in ...

A generalized Langevin equation with quantum heat baths [quantum molecular dynamics (QMD)] for thermal transport is derived with the help of nonequilibrium Green’s function (NEGF) formulation. The exact relationship of the quasiclassical approximation to NEGF is demonstrated using Feynman diagrams...

The local defect structure of NiO nanoparticles was determined by extended x-ray absorption fine structure method. By using the bulk and surface sensitive characterization techniques, we are able to show that the vacancies mostly reside on the surface of the particles and the distribution of vacanci...

The acoustic Faraday rotation in the 4f paramagnet Tb₃Ga₅O₁₂ has recently been observed by Sytcheva (unpublished). As in earlier examples the rotation angle per unit length of transverse acoustic modes was found to depend linearly on sound frequency. Existing theories for this effect consistent...

We analyze the effects of doping holmium impurities into the full-Heusler ferromagnetic alloy Co₂MnSi . Experimental results, as well as theoretical calculations within density functional theory in the local-density approximation generalized to include Coulomb correlation at the mean-field level sh...

The RVO₃ perovskites undergo orbital ordering and orbital-flipping transitions as well as a spin ordering transition. However, the existing model of orbital ordering fails to explain the thermal conductivity, which remains poor and glassy in the orbitally ordered phase. The phonon thermal conducti...

We describe correlator product states, a class of numerically efficient many-body wave functions to describe strongly correlated wave functions in any dimension. Correlator product states introduce direct correlations between physical degrees of freedom in a simple way, yet provide the flexibility t...

The nonstoichiometry of the main structural phase of TiO₂ (rutile) and its natural n -type conductivity is due to oxygen deficiency, which has been explained in terms of native defects, i.e., oxygen vacancies and titanium interstitials. While the latter has been unambiguously identified by electr...

Doping properties of Ag in ZnO were analyzed by first-principles calculations within both the local-density and generalized gradient approximations. The ionization energy of Ag_Zn , about 0.2 eV, is comparable to that of the commonly used group-V acceptors, and is lower than that of two other I^B s...

Molecular dynamics simulations of frictional sliding in an atomic force microscope (AFM) show a clear dependence of superlubricity between incommensurate surfaces on tip compliance and applied normal force. While the kinetic friction vanishes for rigid tips and low normal force, superlubric behavior...

Field emission from carbon nanotubes is studied by propagating the electronic wave function in real time using time-dependent density-functional theory. Complex absorbing potentials have been employed to avoid artificial reflections from the boundaries and to allow long time simulations. Domain deco...

We study the effects of the long-range disorder potential and warping on the conductivity and mobility of graphene ribbons using the Landauer formalism and the tight-binding p -orbital Hamiltonian. We demonstrate that as the length of the structure increases the system undergoes a transition from t...

Spin precession has been used to measure the transmission time τ over a distance L in a graphene sheet. Since conduction electrons in graphene have an energy-independent velocity v , one would expect τ≥L/v . Here we calculate that τlt;L/v at the Dirac point ( =charge neutrality point)...

We have used a femtosecond pump-probe impulsive Raman technique to explore the ultrafast dynamics of micelle suspended single-walled carbon nanotubes (SWNTs) in various pH environments. The structures of coherent phonon spectra of the radial breathing modes exhibit significant pH dependence, to whic...

Double layers of a nanographene with defined molecular structure have been self-assembled at the interface between a molecular solution and the basal plane of graphite. Bias-dependent scanning tunnel microscopy allowed nondestructive imaging of the first or the second or both layers. While the first...

The electronic properties of noninteracting particles moving on a two-dimensional bricklayer lattice are investigated numerically. In particular, the influence of disorder in form of a spatially varying random magnetic flux is studied. In addition, a strong perpendicular constant magnetic field B ...

We analyze the use of layered superconductors as strongly anisotropic metamaterials, which can possess negative refractive index in a wide frequency range. Superconductors are of particular interest because they have the potential to support low losses, which is critical for applications such as super-resolution imaging. We show that low-Tc (s-wave) superconductors can be used to construct layered heterostructures with low losses for T << Tc. However, the real part of their in-plane effective permittivity is very large, making coupling into the structure difficult. Moreover, even at low temperatures, layered high-Tc superconductors have a large in-plane normal conductivity, producing large losses (due to d-wave symmetry). Therefore, it is difficult to enhance the evanescent modes in either low-Tc or high-Tc superconductors.

Multilayer (TiO2)m/(VO2)n nanostructures (d1 - d0 interfaces with no polar discontinuity) show a metal-insulator transition with respect to the VO2 layer thickness in first principles calculations. For n 5 layers, the system becomes metallic, while being insulating for n = 1 and 2. The metal-insulator transition occurs through a semi-Dirac point phase for n = 3 and 4, in which the Fermi surface is point-like and the electrons behave as massless along the zone diagonal in k-space and as massive fermions along the perpendicular direction. We provide an analysis of the evolution of the electronic structure through this unprecedented insulator-to-metal transition, and identify it as resulting from quantum confinement producing a non-intuitive orbital ordering on the V d1 ions, rather than being a specific oxide interface effect. Spin-orbit coupling does not destroy the semi-Dirac point for the calculated ground state, where the spins are aligned along the rutile c-axis, but it does open a substantial gap if the spins lie in the basal plane.

The nonadiabatic quantum tunneling picture, which may be called the many-body Schwinger-Landau-Zener mechanism, for the dielectric breakdown of Mott insulators in strong electric fields is studied in the one-dimensional Hubbard model. The tunneling probability is calculated by a metod due to Dykhne-Davis-Pechukas with an analytical continuation of the Bethe-ansatz solution for excited states to a non-Hermitian case. A remarkable agreement with the time-dependent density matrix renormalization group result is obtained.

In this work we study the localization of vibrational modes in heuristic models for disordered DNA like molecules. Within such approach, atomic groups are replaced by renormalized sites connected by effective springs. The oscillation amplitudes at each site are considered and the localization degree of the normal modes is analyzed by means of the participation ratio, as well as the relative fluctuation of an ensemble of disorder realizations for normal modes in different frequency ranges. The present results suggest that the dynamical properties at low frequencies are completely different for double strand structures compared to single strand ones. Irrespective to disorder, double strand molecules show normal modes with macroscopic localization lengths at low frequencies, for a wide range of spring constants considered in the literature, in contrast to the strong localization in single strands.

We perform density functional theory calculations of electronic core levels to obtain the tellurium X-ray photoelectron spectra in the amorphous solar energy materials CdTeOx (x=0.2,1,2, and 3). We quantify the distribution of local tellurium environments that sum up to the total two-peak structure in the experimental spectrum. The general trend is that the more oxygen neighbors tellurium has the bigger the shift of its core level energy. However, due to the structural complexity, the relation between the core level shift and the number of oxygen neighbors does not obey simple rules. Hence, we show the importance of computer simulations when interpreting X-ray photoelectron spectra in this system in particular, and amorphous oxides in general.

The pressure variation of the structural parameters, u and c/a, of the delafossite CuAlO2 is calculated within the local density approximation (LDA). Further, the electronic structures as obtained by different approximations are compared: LDA, LDA+U, and a recently developed "Quasiparticle self-consistent GW"() approximation. The structural parameters obtained by the LDA agree very well with experiments, but, as expected, gaps in the formal band structure are underestimated as compared to optical experiments. The (in LDA too high lying) Cu-3d states can be down-shifted by LDA+U. The magnitude of the electric field gradient (EFG) as obtained within the LDA is far too small. It can be "fitted" to experiments in LDA+U, but a simultaneous adjustment of the EFG and the gap cannot be obtained with a single U value. QSGW yields reasonable values for both quantities. LDA and QSGW yield significantly different values for some of the band-gap deformation potentials, but calculations within both approximations predict that 3R-CuAlO2 remains an indirect-gap semiconductor at all pressures in its stability range 0 to 36 GPa, although the smallest direct gap has a negative pressure coefficient.

The spectral density of localized states in the band gap of pentacene (trap DOS) was determined with a pentacene-based thin-film transistor from measurements of the temperature dependence and gate-voltage dependence of the contact-corrected field-effect conductivity. Several analytical methods to calculate the trap DOS from the measured data were used to clarify, if the different methods lead to comparable results. We also used computer simulations to further test the results from the analytical methods. Most methods predict a trap DOS close to the valence band edge that can be very well approximated by a single exponential function with a slope in the range of 50-60nbsp;meV and a trap density at the valence band edge of 2times;1021nbsp;eV-1cm-3. Interestingly, the trap DOS is always slightly steeper than exponential. An important finding is that the choice of the method to calculate the trap DOS from the measured data can have a considerable effect on the final result. We identify two specific simplifying assumptions that lead to significant errors in the trap DOS. The temperature-dependence of the band mobility should generally not be neglected. Moreover, the assumption of a constant effective accumulation layer thickness leads to a significant underestimation of the slope of the trap DOS.

Using a combination of modelling and tunneling spectroscopy, we investigate how electrostatic potential fluctuations generated by randomly distributed ionised donors close to a quantum well can produce deep and strongly-confined quantum dot-like potential minima with a rich spectrum of zero-dimensional electronic energy levels. We consider different types of random distribution of donors and how the electronic properties can be controlled and investigated in appropriately-designed double barrier resonant tunneling diodes.

We investigate the power-dependent photoluminescence spectra from a strongly coupled quantum dot-cavity system using a quantum master equation technique that accounts for incoherent pumping, pure dephasing, and fermion or boson statistics. Analytical spectra at the one-photon correlation level and the numerically exact multi-photon spectra for fermions are presented. We compare to recent experiments on a quantum dot - micropillar cavity system and show that an excellent fit to the data can be obtained by varying only the incoherent pump rates in direct correspondence with the experiments. Our theory and experiments together show convincing evidence for stimulated-emission induced broadening and anharmonic cavity-QED.

We report a detailed experimental investigation of the magneto optical properties of different excitonic complexes (neutral exciton, neutral biexciton and charged exciton) confined in self-assembled GaAs/AlGaAs strain free quantum dots grown by droplet epitaxy, where all piezoelectric effects are lacking. We measured the Land#232; g factor and the diamagnetic coefficient g for several quantum dots spanning an interval of ~ 200 meV of the emission energy. The dependence of g factor and g on quantum dot size and shape is discussed together with a comparison with Stranski-Krastanov and fluctuation induced GaAs quantum dots, as well as with excitons confined in quantum wells.

Although optical metamaterials that show artificial magnetism are mesoscopic systems, they are frequently described in terms of effective material parameters. But due to intrinsic nonlocal (or spatially dispersive) effects it may be anticipated that this approach is usually only a crude approximation and is physically meaningless. In order to study the limitations regarding the assignment of effective material parameters, we introduce a technique to retrieve the frequency-dependent elements of the effective permittivity and permeability tensors for arbitrary angles of incidence and apply the method exemplarily to the fishnet metamaterial. It turns out that for the fishnet metamaterial, genuine effective material parameters can only be introduced if quite stringent constraints are imposed on the wavelength/unit cell size ratio. Unfortunately they are only met far away from the resonances that induce a magnetic response required for many envisioned applications of such a fishnet metamaterial. Our work clearly indicates that the mesoscopic nature and the related spatial dispersion of contemporary optical metamaterials that show artificial magnetism prohibits the meaningful introduction of conventional effective material parameters.

The authors report on the photocurrent gain in a diamond photodetector that has two non-ohmic contacts connected back-to-back. This photocurrent gain strongly depends on both the deep-ultraviolet (DUV) light intensity and the applied voltage. In addition, the gain is accompanied by a slow response. The gain is observed to originate from a metal/diamond interface trap center. Numerical analysis discloses that the photocurrent-voltage characteristics follow thermionic-field emission tunneling at low DUV light intensity and field-emission tunneling at high DUV light intensity. The deep traps are thought to produce a thin interface barrier layer at the metal/diamond interface under DUV illumination, which is responsible for the tunneling processes.

We discuss a feedback mechanism between electronic states in a two-electron double quantum dot and the underlying nuclear spin bath. We analyze two pumping cycles for which this feedback provides a force for the Overhauser fields of the two dots to either equilibrate or diverge. Which of these effects is favored depends on the g-factor and Overhauser coupling constant of the material. The strength of the effect increases with the ratio of Overhauser coupling to electron exchange energy and also increases as the external magnetic field decreases.

We have investigated magnetostatic interactions between domain walls in Ni80Fe20 planar nanowires using magnetic soft X-ray microscopy and micromagnetic simulations. In addition to significant monopole-like attraction and repulsion effects we observe that there is coupling of the magnetization configurations of the walls. This is explained in terms of an interaction energy that depends not only on the distance between the walls, but also upon their internal magnetization structure.

We use Scanning Electron Microscopy with Polarization Analysis (SEMPA) to image the magnetic domain structures of individual ferromagnetic nanodisks with different diameters and thicknesses, and thereby determine the phase diagram of the magnetic ground states in these technologically important magnetic structures. Depending on the nanodisk dimensions, we observe magnetic structures based on one of three configurations: a single domain in-plane, a single domain out-of-plane, or a vortex state. By imaging the in-plane and out-of-plane magnetization components of identically prepared Ni80Fe15Mo5 nanodisks with diameters that range from 35 nm to 190 nm and with thicknesses that range from 10 nm to 65 nm, we are able to locate phase boundaries between the three different phases and the triple point. The phase boundaries are not sharply defined, however. Near the boundaries and especially near the triple point, we observe disks in a mixture of the different metastable ground phases, and we observe variations of the basic states, such as a tilted vortex configuration. A magnetic phase diagram generated by a micromagnetic simulation is found to be in good qualitative agreement with the phase diagram determined by the SEMPA measurements. The ability to determine the magnetic phases in sub-100 nm nanodisks enables tailoring material properties and geometry of nanodisks for various potential applications.

The effect of electrical current pulses on magnetic domain walls is studied in a nanometer-scale magnetic track defined in a He+-irradiated Pt/Co(0.5nbsp;nm)/Pt film with out-of-plane anisotropy. Current pulses in a wide range of intensities and durations are shown to result either in track demagnetization, or in polarity-independent domain wall propagation, due to Joule heating during the current pulse. None of the expected spin transfer effects is shown to occur. To explain this, the spin-dependent current density distribution in the stack is evaluated, in the frame of an adapted Fuchs-Sondheimer model. The spin-polarized current density in the cobalt layer is shown to be unexpectedly low as compared to the charge current in the whole stack, which causes Joule heating. This is explained by a low electron transmission at Co/Pt interfaces, as is deduced from resistance measurements on a series of samples with different cobalt thicknesses. This leads us to emphasize that the balance between spin and total charge current densities should be carefully considered when addressing spin transfer torque effects.

We followed the Shastry-Shraiman formulation of Raman scattering in Hubbard systems and considered the Raman intensity profile in the spin-1/2 "perfect" kagom#233; lattice herbertsmithite ZnCu3(OH)6Cl2, assuming the ground state is well-described by the U(1) Dirac spin-liquid state. In the derivation of the Raman T-matrix, we found that the spin chirality term appears in the A2g channel in the kagom#233; lattice at the t4/(wi-U)3 order, but (contrary to the claims by Shastry and Shraiman) vanishes in the square lattice to that order. In the ensuing calculations on the spin-1/2 kagom#233; lattice, we found that the Raman intensity profile in the Eg channel is invariant under an arbitrary rotation in the kagom#233; plane, and that in all (A1g, Eg, and A2g) symmetry channels the Raman intensity profile contains broad continua that display power-law behaviors at low energy, with exponent approximately equal to 1 in the A2g channel and exponent approximately equal to 3 in the Eg and the A1g channels. For the A2g channel, the Raman profile also contains a characteristic 1/w singularity, which arose in our model from an excitation of the emergent U(1) gauge field.

We study a structure consisting of a ferromagnetic (F) layer coupled to two normal metal (N) leads. The system is driven out of equilibrium by the simultaneous application of external DC and AC voltages across the N/F/N structure. Using the Keldysh diagrammatic approach, and modeling the ferromagnet as a classical spin of size S >> 1, we derive the Langevin equation for the magnetization dynamics and calculate the noise correlator. We find that the noise has an explicit frequency dependence in addition to depending on the characteristics of the AC and DC drive. Further, we calculate the current-voltage characteristics of the structure to O(1/S2) and find that the nonequilibrium dynamics of the ferromagnetic layer gives rise to corrections to the current that are both linear and nonlinear in voltage.

We have formulated a relaxation mechanism for ferrites and ferromagnets (insulators and metals) whereby the coupling between the magnetic motion and lattice is based purely on continuum arguments concerning magnetostriction. This theoretical approach contrasts with previous mechanisms based on microscopic formulations of spin-phonon interactions employing a discrete lattice. Our model explains for the first time the scaling of the intrinsic ferromagnetic resonance linewidth with frequency, with temperature { 1/Ms(T) } and the anisotropic nature of magnetic relaxation in ordered magnetic materials. Here, Ms(T) is the thermal saturation magnetization. Without introducing adjustable parameters, our model is in reasonable quantitative agreement with experimental measurements of the intrinsic magnetic resonance linewidths of important class of ordered magnetic materials including both insulators and metals.

We have performed spin polarized calculations of the unexpected ferromagnetism (FM) in ultrathin films of molybdenum dioxide (MoO2) within the framework of density functional theory. It is found that the ideal bulk MoO2 is metallic and non-magnetic. Bulk MoO2 with Mo vacancy, O vacancy, Mo interstitial or O interstitial remains to be non-magnetic. Using slab calculation, we observed ferromagnetism in both oxygen rich and poor MoO2 (100) surfaces with average surface magnetic moment 1.53 and 0.69 mu B per surface Mo atom, respectively. The partial density of states of surface Mo atom at the Fermi level (EF) is much larger than that of the Mo atom in the center of the slab and in bulk MoO2, which indicates that ferromagnetism in surface (100) is due to Stoner instability. Enrichment of oxygen at the surface is found to be more favorable for ferromagnetism in MoO2 (100). The 2p-states of surface oxygen atoms are significantly hybridized with the 4d states of Mo atoms and are appreciably spin-polarized.

We study graphene antidot lattices - superlattices of perforations (antidots) in a graphene sheet - using a model that accounts for the phonon-modulation of the p-electron hopping integrals. We calculate the phonon spectra of selected antidot lattices using two different semi-empirical methods. Based on the adopted model, we quantify the nature of charge carriers in the system by computing the quasiparticle weight due to the electron-phonon interaction for an excess electron in the conduction band. We find a very strong phonon-induced renormalization, with the effective electron masses exhibiting nonmonotonic dependence on the superlattice period for a given antidot diameter. Our study provides an indication of polaronic behavior and points to the necessity of taking into account the inelastic degrees of freedom in future studies of transport in graphene antidot lattices.

A method for studying spatially and temporally resolved many-body dynamics of charge carriers in carbon nanotubes is presented. We derive coherent, spatially inhomogeneous Bloch equations for charge carrier dynamics in an optically excited carbon nanotube. By solving the equations of motion numerically under spatially inhomogeneous excitation conditions, we also demonstrate a striking difference in carrier drift velocity for excitation at the exciton resonance and above the band edge.

We have measured local and non-local conductance of mesoscopic normal-metal/superconductor hybrid structures fabricated by e-beam lithography and shadow evaporation. The sample geometry consists of a superconducting aluminum bar with two normal-metal wires forming tunnel contacts to the aluminum at distances of the order of the superconducting coherence length. We observe subgap anomalies in both local and non-local conductance that quickly decay with magnetic field and temperature. For the non-local conductance both positive and negative signs are found as a function of bias conditions, indicating at a competition of crossed Andreev reflection and elastic cotunneling. Our data suggest that the signals are caused by a phase-coherent enhancement of transport rather than dynamical Coulomb blockade.

In a new type of superconductors, type-1.5 materials, vortices emerge in clusters, which make characteristic evolution with increasing magnetic field. These novel vortex clusters and their field dependence are directly visualized by scanning SQUID microscopy at very low vortex densities in MgB2 single crystals. Our observations are elucidated by simulations based on a two-gap Ginzburg-Landau (GL) theory in the type-1.5 regime.

The influence of random pinning on the vortex dynamics in a periodic square potential under an external drive is investigated. Using numerical experiments and theoretical approach, we found several dynamical regimes of vortex motion that are different from the ones for a regular pinning potential. Vortex transfer is controlled by kinks and antikinks, which either preexist in the system or appear spontaneously in pairs and then propagate. When kinks and antikinks collide, they annihilate. We provide clear physical interpretations of the observed features.

We describe two different nuclear quadrupole resonance (NQR) based techniques, designed to measure the local asymmetry of the internal electric field gradient η and the tilt angle α of the main NQR principal axis ẑ from the crystallographic axis ĉ . These techniques use the dependence o...

We examine the appearance of a spontaneous bulk spin current in a triplet superconductor in contact with a metallic ferromagnet. The spin current results from the spin flip of Cooper pairs upon reflection from the interface with the ferromagnet, and is shown to display strong similarities to the spo...

We have studied a three-unit-cell-thick YBa₂Cu₃O_7−δ (YBCO) superconducting film grown on a slightly vicinal SrTiO₃ substrate that was polished from the (001) plane by a small miscut angle (less than 0.5° ). This produced, on its surface, a linear array of single-unit-cell-high steps with a ...

The acoustic Faraday rotation in the 4f paramagnet Tb₃Ga₅O₁₂ has recently been observed by Sytcheva (unpublished). As in earlier examples the rotation angle per unit length of transverse acoustic modes was found to depend linearly on sound frequency. Existing theories for this effect consistent...

We report inelastic x-ray scattering experiments on the lattice dynamics in SmFeAsO and superconducting SmFeAsO_0.60F_0.35 single crystals. Particular attention was paid to the dispersions along the [100] direction of three optical modes close to 23 meV, polarized out of the FeAs planes. Remarkably,...

We derive boundary conditions for the electrically induced spin accumulation in a finite, disordered two-dimensional semiconductor channel. While for dc electric fields these boundary conditions select spatially constant spin profiles equivalent to a vanishing spin-Hall effect, we show that an in-pl...

We calculate the transmission of electrons and holes between two normal-metal (N) electrodes, separated over a distance L by an impurity-free superconductor (S) with d -wave symmetry of the order parameter. Nodal lines of vanishing excitation gap form ballistic conduction channels for coupled ele...

In this paper we provide a comprehensive analysis of different properties of pnictides both in the normal and superconducting state, with a particular focus on the optimally doped Ba_1−xK_xFe₂As₂ system. We show that, by using the band dispersions experimentally measured by angle-resolved photoemi...

Photoluminescence studies of a wide asymmetric quantum well hosting two strongly coupled electron layers demonstrate unambiguously how such a system deforms itself due to interlayer charge transfer in a quantizing magnetic field thus manifesting its overall single-layer appearance. The charge distri...

Photoexcited dynamics of a spin-density-wave (SDW) state in an organic linear-chain compound bis-(tetramethyl-tetraselenafulvalene)hexafluorophosphate, (TMTSF)₂PF₆ , is investigated by optical pump and terahertz probe experiments. After the ultrashort laser-pulse excitation, a sudden closing follow...