发表机构
Xiamen University Malaysia; University of Connecticut; National Synchrotron Light Source II, Brookhaven National Lab（马来西亚厦门大学; 康涅狄格大学; 布鲁克海文国家实验室国家同步光源II）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用ARPES揭示1T-TaS2中C-CDW到NC-CDW相变时隙内态发生滞回性塌缩与恢复，提供了一阶相变的直接谱学证据，并表明其与电阻率变化及电子重构密切相关。
AI 中文摘要
1T-TaS2中近公度（NC-CDW）与公度（C-CDW）电荷密度波相之间的一阶相变支撑了其奇异的电子行为，然而，跨越这一相变时低能电子结构的谱学演化仍然至关重要。利用角分辨光电子能谱（ARPES），我们研究了低温C-CDW相，其特征是通常与下哈伯德带相关的平带以及一个位于费米能级附近、截然不同的隙内态。光子能量依赖的测量通过它们不同的谱权重演化区分了这两个低能特征。在加热和冷却循环中的温度依赖ARPES显示，隙内态在加热进入NC-CDW相时发生突然塌缩，并在冷却回C-CDW相时急剧重新出现。这种显著的 thermal 滞回提供了该相变一阶性质的直接谱学证据。此外，隙内态的消失与恢复紧密跟踪电阻率的相应变化，突显了它与跨越C-CDW/NC-CDW相变的电子重构的密切关联。
英文摘要
The first order phase transition between the nearly commensurate (NC-CDW) and commensurate (C-CDW) charge density wave phases in 1T-TaS2 underpins its exotic electronic behavior, yet the spectroscopic evolution of the low energy electronic structure across this transition remains crucial to understand. Using angle resolved photoemission spectroscopy (ARPES), we investigate the low temperature C-CDW phase, characterized by a flat band commonly associated with the lower Hubbard band and a distinct in-gap state located closer to the Fermi level. Photon energy dependent measurements distinguish these two low energy features through their different spectral weight evolution. Temperature dependent ARPES across heating and cooling cycles reveals that the in-gap state undergoes an abrupt collapse upon heating into the NC-CDW phase and re-emerges sharply upon cooling back into the C-CDW phase. This pronounced thermal hysteresis provides direct spectroscopic evidence of the first order nature of the transition. Furthermore, the disappearance and recovery of the in-gap state closely track the corresponding changes in resistivity, highlighting its intimate connection to the electronic reconstruction across the C-CDW/NC-CDW phase transition.
Comments6 pages, 4 figures
