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

Abstract

In this paper, we explore some structural phase transitions in \textit{GaAs}-based coupled electron-electron ({\it e-e}) and electron-hole ({\it 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 {\it et al} (the qSTLS theory), and the results have been compared with the static STLS model.
It has been found that in the {\it 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 $q\sim 3.5k_{Fe}$. However, a charge-density-wave (CDW) instability is observed at $q\sim 2k_{Fe}$ when the xc are treated statically ($k_{Fe}$ being the electron's Fermi wave vector). On the other hand, the {\it 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 {\it e-e} system at the investigated parameters. Expectedly, the quantum phase transitions are predicted to occur in the strongly correlated regime {\it i.e.} at sufficiently small $T$ and high $r_{se}$.

Dependence temperature on effective mass and susceptibility in quantum well-wires

“…Under strong laser pulse excitation, these materials exhibit exchange-correlation effects, along with the Coulomb interaction, leading to nonlinear optical phenomena [19][20][21]. The key components directly affecting the optical spectrum are mass and susceptibility, by calculating the imaginary part of the frequency-dependent optical susceptibility and mass, we obtain absorption or photoluminescence spectra [22][23][24].…”