Suppression of a charge-density-wave ground state in high magnetic fields: Spin and orbital mechanisms

The charge density wave, (CDW) transition temperature in the quasi-one-dimensional (Q1D) organic material (Per)(2)Au(mnt)(2) is relatively low (T-CDW similar to 12 K). Hence in a mean field BCS model, the CDW state should be completely suppressed in magnetic fields of order 30-40 T. To explore this possibility, the magnetoresistance of (Per)(2)Au(mnt)(2) was investigated in magnetic fields to 45 T for 0.5 K < T < 12 K. For fields directed along the Q1D molecular stacking direction, T-CDW decreases with field, terminating at about similar to37.T for temperatures approaching zero. Results for this field orientation are in general agreement with theoretical predictions, including the field dependence of the magnetoresistance and the energy gap, Delta(CDW). However, for fields tilted away from the stacking direction, orbital effects arise above 15 T that may be related to the return of un-nested Fermi surface sections that develop as the CDW state is suppressed. These findings are consistent with expectations that Q1D metallic behavior will return outside the CDW phase boundary.