论文标题
合成双层光学晶格中扁平频段诱导的超导性
Flat-band-induced superconductivity in synthetic bilayer optical lattices
论文作者
论文摘要
将两层具有相对扭曲角的石墨烯堆叠会产生Moiré模式，这可以强烈改变电子行为，并可能导致非常规的超导性。扭曲的双层的合成版本可以在光学晶格中用冷原子设计。在这里，通过在原子级别之间的耦合来模仿双层结构，并且通过这种耦合的空间调制来实现扭曲。在本文中，我们研究了这种合成的双层晶格中费米原子的超导行为。原子之间的有吸引力的相互作用在平均场水平上进行治疗，并通过自以为是确定的配对缝隙来分析超导行为。当准平台带结构发生在费米表面上时，发现了配对间隙的强大增强，这反映了扭曲对超导性的突出作用。相互作用的可调性允许将超导相关性从内部（合成）层转换为间（合成）层。这还包括中间场景，其中层间耦合之间的竞争完全破坏了超导行为，从而导致相互作用调整后重新进入超导性
Stacking two layers of graphene with a relative twist angle gives rise to moiré patterns, which can strongly modify electronic behavior and may lead to unconventional superconductivity. A synthetic version of twisted bilayers can be engineered with cold atoms in optical lattices. Here, the bilayer structure is mimicked through coupling between atomic sublevels, and the twist is achieved by a spatial modulation of this coupling. In the present paper, we investigate the superconducting behavior of fermionic atoms in such a synthetic twisted bilayer lattice. Attractive interactions between the atoms are treated on the mean-field level, and the superconducting behavior is analyzed via the self-consistently determined pairing gap. A strong enhancement of the pairing gap is found, when a quasi-flat band structure occurs at the Fermi surface, reflecting the prominent role played by the twist on the superconductivity. The tunability of interactions allows for the switching of superconducting correlations from intra (synthetic) layer to inter (synthetic) layer. This includes also the intermediate scenario, in which the competition between inter- and intra-layer coupling completely destroys the superconducting behavior, resulting in re-entrant superconductivity upon tuning of the interactions
