Charge Density Waves in a Quantum Plasma

TL;DR

This paper investigates charge and spin density wave instabilities in a two-component quantum plasma using density functional theory, revealing phase transitions and scaling relations across different mass ratios.

Contribution

It introduces a detailed analysis of CDW and SDW instabilities in quantum plasmas with varying mass ratios, including phase diagrams and scaling laws.

Findings

Identification of leading unstable CDW modes in 2D and 3D

Discovery of exotic quantum phase transitions with discontinuous wave-vector ranges

Development of phase diagrams and a scaling relation for different mass ratios

Abstract

We analyze the instability of an unpolarized uniform quantum plasma consisting of two oppositely charged fermionic components with varying mass ratios, against charge and spin density waves (CDWs and SDWs). Using density functional theory, we treat each component with the local spin density approximation and a rescaled exchange-correlation functional. Interactions between different components are treated with a mean-field approximation. In both two- and three-dimensions, we find leading unstable CDW modes in the second-order expansion of the energy functional, which would induce the transition to quantum liquid crystals. The transition point and the length of the wave-vector are computed numerically. Discontinuous ranges of the wave-vector are found for different mass ratios between the two components, indicating exotic quantum phase transitions. Phase diagrams are obtained and a scaling relation is proposed to generalize the results to two-component fermionic plasmas with any mass scale. We discuss the implications of our results and directions for further improvement in treating quantum plasmas.