单层TaIrTe$_4$中的准一维拓扑能带结构与范霍夫奇点：来自激光微聚焦角分辨光电子能谱的研究
Quasi-one-dimensional topological band structure and van Hove singularities in monolayer TaIrTe$_4$ from laser $μ$-ARPES
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中文总结 AI 辅助
本研究利用激光μ-ARPES表征单层1T-TaIrTe$_4$的电子结构，发现其能带具强各向异性且存在态密度鞍点，表明范霍夫奇点与电子关联在该材料输运相图中仅起次要作用。
中文摘要 AI 辅助
近期输运实验报道，在偏离电荷中性的栅压调控下，单层1T-TaIrTe$_4$中存在量子自旋霍尔绝缘体相。该相无法通过能带结构计算预测，被归因于范霍夫奇点处强关联诱导的电子不稳定性。本研究采用微聚焦激光角分辨光电子能谱（μ-ARPES）研究机械剥离的单层1T-TaIrTe$_4$的电子结构，发现其具有易受密度波不稳定性影响的强各向异性能带结构，且态密度中存在鞍点奇点。但该鞍点对应的载流子密度下，输运实验未观测到异常；准粒子线宽则表明仅存在弱电子关联。这说明范霍夫奇点与电子关联在单层1T-TaIrTe$_4$的输运相图中仅起次要作用。
英文摘要
Recent transport experiments reported a quantum spin Hall insulator phase in monolayer 1T-TaIrTe$_4$ gated away from charge neutrality. This phase is not predicted by band structure calculations and has been attributed to an electronic instability induced by strong correlations at a putative van Hove singularity. Here, we investigate the electronic structure of exfoliated monolayer 1T-TaIrTe$_4$ using micro-focus laser angle resolved photoemission. We find a strongly anisotropic band structure susceptible to density wave instabilities. Our data further reveal a saddle point singularity in the density of states. However, we find that the saddle point lies at a density for which transport experiments found no anomalies. Moreover, the quasiparticle line widths suggest weak electron correlations only. This points to a secondary role of van Hove singularities and electron correlations in the transport phase diagram of monolayer 1T-TaIrTe$_4$.
