Anomalous magnetoresistance anisotropy in metallic and spin-density-wave phases of the quasi-one-dimensional organic conductor (TMTSF)2ClO4

Abstract

We report new features of the transverse magnetoresistance (MR) anisotropy in (TMTSF${)}_2$ ${\mathrm{ClO}}_4$ in both the metallic phase and field-induced spin-density-wave (FISDW) phases. In the metallic phase, the MR varies as Δ$R_{\mathrm{xx}}$∝$H^{\alpha }$ where α<2 and α decreases as the magnetic field is tilted from the $c^{\mathrm{*}}$ axis. In the FISDW states, there is a dramatic enhancement of the MR anomalies at the FISDW phase transitions as the magnetic field is tilted, with particular angles for stronger and weaker enhancement. This is clear experimental evidence that the FISDW phases are not simply 2D in nature.