arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2203.01010cond-mat.str-el
收藏

3L-MoTe2/WSe2中的Pomeranchuk效应与可调量子相变

Pomeranchuk Effect and Tunable Quantum Phase Transitions in 3L-MoTe2/WSe2

Mingjie Zhang, Xuan Zhao, Kenji Watanabe, Takashi Taniguchi, Zheng Zhu, Fengcheng Wu, Yongqing Li, Yang Xu

AI总结:

本研究在3L-MoTe2/WSe2三角莫尔超晶格中通过电输运测量证实了Pomeranchuk效应,发现电场和磁场可分别诱导Lifshitz相变和金属-绝缘体相变,揭示了该系统在中等相互作用强度下的丰富量子临界特性。

摘要:

许多备受瞩目的奇异物质态通常在量子相变附近涌现,例如量子自旋液体(QSL)和非常规超导性。因此,实验上探索能够连续跨越这些相变进行调控的系统备受期望。在此,我们展示了这种可调性以及三层MoTe2与单层WSe2(3L-MoTe2/WSe2)之间形成的三角莫尔超晶格中的电子关联效应。通过电输运测量,我们确凿地证实了在第一个莫尔子带半填充时观察到的Pomeranchuk效应,即温度升高反而反常地增强了电荷局域化。该系统同时表现出具有强重整化有效质量的Fermi液体特征,表明其处于一种关联金属态。该状态对垂直平面的电场和磁场高度敏感,分别引发Lifshitz相变和金属-绝缘体相变(MIT)。这使得能够在基础温度下确定量子相图中的一个三临界点。我们通过施加垂直电场引起的层间电荷转移来解释Lifshitz相变,这导致了新费米面的出现以及Pomeranchuk效应的即刻抑制。电阻的标度行为支持了磁场诱导的MIT中量子临界性的存在。我们的研究表明,3L-MoTe2/WSe2位于三角晶格Hubbard模型的MIT点附近,使其成为展现中等相互作用强度下丰富关联效应的独特系统。

英文摘要:

Many sought-after exotic states of matter are known to emerge close to quantum phase transitions, such as quantum spin liquids (QSL) and unconventional superconductivity. It is thus desirable to experimentally explore systems that can be continuously tuned across these transitions. Here, we demonstrate such tunability and the electronic correlation effects in triangular moiré superlattices formed between trilayer MoTe$_2$ and monolayer WSe$_2$ (3L-MoTe$_2$/WSe$_2$). Through electric transport measurements, we firmly establish the Pomeranchuk effect observed at half filling of the first moiré subband, where increasing temperature paradoxically enhances charge localization. The system simultaneously exhibits the characteristic of a Fermi liquid with strongly renormalized effective mass, suggesting a correlated metal state. The state is highly susceptible to out-of-plane electric and magnetic fields, which induce a Lifshitz transition and a metal-insulator transition (MIT), respectively. It enables identification of a tricritical point in the quantum phase diagram at the base temperature. We explain the Lifshitz transition in terms of interlayer charge transfer by applying the vertical electric field, which leads to the emergence of a new Fermi surface and immediate suppression of the Pomeranchuk effect. The existence of quantum criticality in the magnetic filed induced MIT is supported by scaling behaviors of the resistance. Our work shows the 3L-MoTe$_2$/WSe$_2$ lies in the vicinity to the MIT point of the triangular lattice Hubbard model, rendering it a unique system to manifest the rich correlation effects at an intermediate interaction strength.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑