{"title":"Topological superfluid phases of attractive Fermi-Hubbard model in narrow-band cold-atom optical lattices","authors":"T. D. Stanescu, Sumanta Tewari, V. W. Scarola","doi":"arxiv-2408.16210","DOIUrl":null,"url":null,"abstract":"We investigate the effects of attractive Hubbard interaction on two-component\nfermionic atoms in narrow two-dimensional (2D) energy bands that exhibit Rashba\nspin-orbit coupling (SOC) in the presence of an applied Zeeman field. This\nnarrow-band 2D spin-orbit coupled attractive Fermi-Hubbard model can\npotentially be realized in cold atom systems in optical lattices with\nartificially engineered Rashba SOC and Zeeman field. Employing a\nself-consistent mean field approximation for the pairing potential, we uncover\na complex phase diagram featuring various topological superfluid (TS) phases,\ndependent on the chemical potential and the Zeeman field. We focus on the\npairing potential and the corresponding quasiparticle gap characterizing the TS\nphases, which are notably small for a wide-band model with quadratic dispersion\nnear the $\\Gamma$-point, as found in earlier work, and we identify the\nparameter regimes that maximize the gap. We find that, while generally the\nvalue of the pairing potential increases with the reduction of the fermionic\nbandwidth, as expected for narrow- or flat-band systems, the magnitude of the\ntopological gap characterizing the TS phases reaches a maximum of about\n$10-12.5\\%$ of the interaction strength at finite values of the hopping\namplitude, Rashba coupling, and Zeeman field.","PeriodicalId":501521,"journal":{"name":"arXiv - PHYS - Quantum Gases","volume":"3 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"arXiv - PHYS - Quantum Gases","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/arxiv-2408.16210","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
We investigate the effects of attractive Hubbard interaction on two-component
fermionic atoms in narrow two-dimensional (2D) energy bands that exhibit Rashba
spin-orbit coupling (SOC) in the presence of an applied Zeeman field. This
narrow-band 2D spin-orbit coupled attractive Fermi-Hubbard model can
potentially be realized in cold atom systems in optical lattices with
artificially engineered Rashba SOC and Zeeman field. Employing a
self-consistent mean field approximation for the pairing potential, we uncover
a complex phase diagram featuring various topological superfluid (TS) phases,
dependent on the chemical potential and the Zeeman field. We focus on the
pairing potential and the corresponding quasiparticle gap characterizing the TS
phases, which are notably small for a wide-band model with quadratic dispersion
near the $\Gamma$-point, as found in earlier work, and we identify the
parameter regimes that maximize the gap. We find that, while generally the
value of the pairing potential increases with the reduction of the fermionic
bandwidth, as expected for narrow- or flat-band systems, the magnitude of the
topological gap characterizing the TS phases reaches a maximum of about
$10-12.5\%$ of the interaction strength at finite values of the hopping
amplitude, Rashba coupling, and Zeeman field.