Theory of Field-Induced Spin Density Wave States in Anisotropic Two-Dimensional Electron Systems

Abstract

In order to explain recursive cascades of the field-induced spin density wave phase in organic conductors (TMTSF) 2 X discovered recently, a standard model or two-dimensional anisotropic Hubbard model under a perpendicular field is investigated theoretically: The field-induced SDW ground state is in general to be characterized by a set of countable many order parameters (OP) of the Fourier components of the SDW modulation or by a distribution of these OP's. Due to interference between the lattice commensurability and magnetic length the OP distribution differs for every rational field, resulting in a phase diagram with devil's staircase like infinite cascades. The band structure and spatial profile of the FISDW are analyzed and compared with ordinary density wave states.