Edge and bulk electron states in a quasi-one-dimensional metal in a magnetic field: The semi-infinite Wannier-Stark ladder

We study edge and bulk open-orbit electron states in a quasi-one-dimensional (Q1D) metal subject to a magnetic field. For both types of states, the energy spectrum near the Fermi energy consists of two terms. One term has a continuous dependence on the momentum along the chains, whereas the other term is quantized discretely. The discrete energy spectrum is mathematically equivalent to the Wannier-Stark energy ladder of a semi-infinite 1D lattice in an effective electric field. We solve the latter problem analytically in the semiclassical approximation and by numerical diagonalization. We show explicitly that equilibrium electric currents vanish both at the edges and in the bulk, so no orbital magnetization is expected in a Q1D metal in a magnetic field.