Hubbard model on a triangular lattice at finite temperatures

Fuente: arXiv
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Main Author: Sherman, A.
Format: Preprint
Published: 2024
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author Sherman, A.
author_facet Sherman, A.
contents Using the strong coupling diagram technique, we find three phases of the half-filled isotropic Hubbard model on a triangular lattice at finite temperatures. The weak-interaction ($U\lesssim5t$) and strong-interaction ($U\gtrsim9t$) phases are similar to those obtained by zero-temperature methods -- the former is a metal without perceptible spin excitations; the latter is a Mott insulator with the 120$^\circ$ short-range spin ordering. Zero-temperature approaches predict a nonmagnetic insulating spin-liquid phase sandwiched between these two regions. In our finite-temperature calculations, the Mott gap in the intermediate phase is filled by the Fermi-level peak, which is a manifestation of the bound states of electrons with pronounced spin excitations. We relate the appearance of these excitations at finite temperatures to the Pomeranchuk effect.
format Preprint
id arxiv_https___arxiv_org_abs_2406_13289
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Hubbard model on a triangular lattice at finite temperatures
Sherman, A.
Strongly Correlated Electrons
Using the strong coupling diagram technique, we find three phases of the half-filled isotropic Hubbard model on a triangular lattice at finite temperatures. The weak-interaction ($U\lesssim5t$) and strong-interaction ($U\gtrsim9t$) phases are similar to those obtained by zero-temperature methods -- the former is a metal without perceptible spin excitations; the latter is a Mott insulator with the 120$^\circ$ short-range spin ordering. Zero-temperature approaches predict a nonmagnetic insulating spin-liquid phase sandwiched between these two regions. In our finite-temperature calculations, the Mott gap in the intermediate phase is filled by the Fermi-level peak, which is a manifestation of the bound states of electrons with pronounced spin excitations. We relate the appearance of these excitations at finite temperatures to the Pomeranchuk effect.
title Hubbard model on a triangular lattice at finite temperatures
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2406.13289