The Hall conductivity in unconventional charge density wave systems

TL;DR

This paper investigates how unconventional charge density waves with d-wave symmetry affect the Hall conductivity, revealing an additional mass term that is significant near hot spots in the electronic structure.

Contribution

It introduces a new theoretical framework for understanding the Hall conductivity in DDW states, highlighting the role of inter-branch currents and hot spot effects.

Findings

The Hall conductivity includes an extra mass term due to inter-branch currents.

Numerical calculations show the mass term is enhanced near hot spots.

The extra mass term significantly influences the Hall number in DDW states.

Abstract

Charge density waves with unconventional order parameters, for instance, with d-wave symmetry (DDW), may be relevant in the underdoped regime of high-T_c cuprates or other quasi-one or two dimensional metals. A DDW state is characterized by two branches of low-lying electronic excitations. The resulting quantum mechanical current has an inter-branch component which leads to an additional mass term in the expression for the Hall conductivity. This extra mass term is parametrically enhanced near the ``hot spots'' of fermionic dispersion and is non-neglegible as is shown by numerical calculations of the Hall number in the DDW state.