Abstract

We study competing orders of spinless fermions in the triangular-lattice Hubbard model with nearest-neighbor interaction. We calculate the effective, momentum-resolved two-particle vertex in an unbiased way in terms of the functional renormalization group method and compare two different schemes for the momentum discretization, one based on dividing the Fermi surface into patches and one based on a channel decomposition. We study attractive and repulsive nearest-neighbor interaction and find a competition of pairing and charge instabilities. In the attractive case, a Pomeranchuk instability occurs at Van Hove filling and f-wave and p-wave pairing emerge when the filling is reduced. In the repulsive case, we obtain a charge density wave at Van Hove filling and extended p-wave pairing with reduced filling. The p-wave pairing solution is doubly degenerate and can realize chiral \(p+ip\) superconductivity with different Chern numbers in the ground state. We discuss implications for strongly correlated spin-orbit coupled hexagonal electron systems such as moiré heterostructures.

Graphic Abstract

中文翻译：

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无自旋三角晶格费米子的功能重整化：N-patch vs. truncated-unity scheme

摘要

我们研究了具有最近邻相互作用的三角形晶格 Hubbard 模型中无自旋费米子的竞争顺序。我们根据功能重整化组方法以无偏的方式计算有效的、动量解析的两粒子顶点，并比较了两种不同的动量离散化方案，一种基于将费米面划分为块，另一种基于通道分解. 我们研究了吸引和排斥的最近邻相互作用，并发现了配对和电荷不稳定性的竞争。在有吸引力的情况下，Van Hove 填充出现 Pomeranchuk 不稳定性，当填充减少时出现f波和p波配对。在排斥的情况下，我们在 Van Hove 填充和扩展p处获得电荷密度波- 减少填充的波配对。p波配对解是双简并的，可以在基态实现不同陈数的手性\(p+ip\)超导。我们讨论了对强相关自旋轨道耦合六方电子系统（如莫尔异质结构）的影响。

图形摘要