Quantum Hall effect anomaly and collective modes in the magnetic-field-induced spin-density-wave phases of quasi-one-dimensional conductors

TL;DR

This paper investigates collective excitations in magnetic-field-induced spin-density-wave phases of quasi-one-dimensional conductors, revealing additional modes linked to quantum Hall effect anomalies and their impact on charge and spin responses.

Contribution

It identifies new collective modes arising from coexisting spin-density waves in FISDW phases, especially in the presence of the Ribault anomaly, and discusses their experimental implications.

Findings

Additional collective modes are present in phases with quantum Hall effect sign reversal.

These modes influence charge and spin response functions significantly.

Experimental consequences for Bechgaard salts are discussed.

Abstract

We study the collective modes in the magnetic-field-induced spin-density-wave (FISDW) phases experimentally observed in organic conductors of the Bechgaard salts family. In phases that exhibit a sign reversal of the quantum Hall effect (Ribault anomaly), the coexistence of two spin-density waves gives rise to additional collective modes besides the Goldstone modes due to spontaneous translation and rotation symmetry breaking. These modes strongly affect the charge and spin response functions. We discuss some experimental consequences for the Bechgaard salts.