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Superconductivity, pseudogap, and phase separation in topological flat bands: a quantum Monte Carlo study

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 نشر من قبل Johannes Hofmann S
 تاريخ النشر 2019
  مجال البحث فيزياء
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We study a two-dimensional model of an isolated narrow topological band at partial filling with local attractive interactions. Numerically exact quantum Monte Carlo calculations show that the ground state is a superconductor with a critical temperature that scales nearly linearly with the interaction strength. We also find a broad pseudogap regime at temperatures above the superconducting phase that exhibits strong pairing fluctuations and a tendency towards electronic phase separation; introducing a small nearest neighbor attraction suppresses superconductivity entirely and results in phase separation. We discuss the possible relevance of superconductivity in this unusual regime to the physics of flat band moir{e} materials, and as a route to designing higher temperature superconductors.



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