High magnetic field induced charge density wave states in a quasi-one dimensional organic conductor

TL;DR

This study investigates how high magnetic fields induce complex charge density wave states in a quasi-one-dimensional organic conductor, revealing a transition from a suppressed CDW to a new density wave phase with sub-phases, and re-entrant low resistance states.

Contribution

It provides experimental evidence of field-induced charge density wave states in a Q1D organic conductor, expanding understanding of magnetic field effects on low-dimensional electronic systems.

Findings

Charge density wave state suppressed at ~20 T by magnetic field.

Observation of a new density wave state with sub-phases between 20-50 T.

Re-entrant low resistance state at fields above 50 T.

Abstract

We have measured the high field magnetoresistence and magnetization of quasi-one- dimensional (Q1D) organic conductor (Per)2Pt(mnt)2 (where Per = perylene and mnt = maleonitriledithiolate), which has a charge density wave (CDW) ground state at zero magnetic field below 8 K. We find that the CDW ground state is suppressed with moderate magnetic fields of order 20 T, as expected from a mean field theory treatment of Pauli effects[W. Dieterich and P. Fulde, Z. Physik 265, 239 - 243 (1973)]. At higher magnetic fields, a new, density wave state with sub-phases is observed in the range 20 to 50 T, which is reminiscent of the cascade of field induced, quantized, spin density wave phases (FISDW) observed in the Bechgaard salts. The new density wave state, which we tenatively identify as a field induced charge density wave state (FICDW), is re-entrant to a low resistance state at even higher fields, of order 50 T and above. Unlike the FISDW ground state, the FICDW state is only weakly orbital, and appears for all directions of magnetic field. Our findings are substantiated by electrical resistivity, magnetization, thermoelectric, and Hall measurements. We discuss our results in light of theoretical work involving magnetic field dependent Q1D CDW ground states in high magnetic fields [D. Zanchi, A. Bjelis, and G. Montambaux, Phys. Rev. B 53, (1996)1240; A. Lebed, JETP Lett. 78,138(2003)].