Theory of Coulomb driven nematicity in a multi-valley two-dimensional electron gas

Autor:	Calvera, Vladimir, Valenti, Agnes, Huber, Sebastian D., Berg, Erez, Kivelson, Steven A.
Rok vydání:	2024
Předmět:	Condensed Matter - Strongly Correlated Electrons Condensed Matter - Mesoscale and Nanoscale Physics Condensed Matter - Statistical Mechanics
Druh dokumentu:	Working Paper
Popis:	The properties of a two-dimensional electron gas (2DEG) in a semiconductor host with two valleys related by an underlying $C_4$ rotational symmetry are studied using Hartree-Fock (HF) and various other many-body approaches. A familiar artifact of the HF approach is a degeneracy between the valley polarized - ``Ising nematic'' - and spin polarized - ferromagnetic - phases, which is inconsistent with recent variational Monte Carlo (VMC) results. Correlation effects, computed either within the random phase approximation (RPA) or the T-matrix approximation, enhance the valley susceptibility relative to the spin susceptibility. Extrapolating the results to finite interaction strength, we find a direct first-order transition from a symmetry-unbroken state to a spin unpolarized Ising nematic fluid with full valley polarization, in qualitative agreement with VMC. The RPA results are also reminiscent of experiments on the corresponding 2DEG in AlAs heterostructures. Comment: 6 + 21 pages, 12 figures
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/2406.12825 Zobrazit plný text záznamu View this record from Arxiv