On some structural phase transitions in coupled quantum wires at finite temperature

• Published in: Physica scripta 2024-04, Vol.99 (4), p.45914
• Main Authors: Rani, Preeti, Kaur, Kulveer, Garg, Vinayak, Moudgil, R K
• Format: Article
• Language: English
• Subjects: charge-density-wave; coupled quantum wires; exchange-correlations; pair-correlation function; susceptibility; Wigner crystallization
• ISSN: 0031-8949; 1402-4896
• DOI: 10.1088/1402-4896/ad2da3

In this paper, we explore some structural phase transitions in GaAs -based coupled electron-electron ( e-e ) and electron-hole ( e-h ) quantum wires at finite temperature. To this endeavour, the intra- and inter-wire static-structure factors, pair-correlation functions and static (charge) density susceptibilities are calculated over a wide range of temperature T , particle number density parameter r se and some selected values of inter-wire spacing d . The particle exchange-correlations (xc) are included using the dynamic version of self-consistent mean-field theory of Singwi et al (the qSTLS theory), and the results have been compared with the static STLS model. It has been found that in the e-h system, the inclusion of dynamic nature of xc leads to the formation of Wigner crystal (WC) state in the close proximity of two wires at wave-vector q ∼ 3.5 k Fe . However, a charge-density-wave (CDW) instability is observed at q ∼ 2 k Fe when the xc are treated statically ( k Fe being the electron’s Fermi wave vector). On the other hand, the e-e system shows comparatively small signatures of the WC phase when wires are kept sufficiently far apart, but, a long-wavelength instability is encountered in close vicinity of the wires. Interestingly, the CDW phase is completely missing in the e-e system at the investigated parameters. Expectedly, the quantum phase transitions are predicted to occur in the strongly correlated regime i.e. at sufficiently small T and high r se .