Magnetic field dependence of the threshold electric field in unconventional charge density waves

Abstract

Many experiments suggest that the unidentified low-temperature phase of $\alpha -(\mathrm{BEDT}-\mathrm{TTF}{)}_2\mathrm{KHg}(\mathrm{SCN}{)}_4$ is most likely unconventional charge density wave (UCDW). To further extend this identification we present our theoretical study of the threshold electric field of UCDW in a magnetic field. The magnetic field-temperature phase diagram is very similar to those in a d-wave superconductor. The optical conductivity shows clear features characteristic to both UDW and magnetic field. We find a rather strong field dependence of the threshold electric field, which shows qualitatively good agreement with the experimental data.