Dimensionality-driven power-law gap in the bilayer TaTe2 grown by molecular-beam epitaxy

IF 5.3 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

APL Materials Pub Date : 2024-07-02 DOI:10.1063/5.0213957

Bruno Kenichi Saika, Satoshi Yoshida, Markel Pardo-Almanza, Natsuki Mitsuishi, Masato Sakano, Yuita Fujisawa, Yue Wang, Yoshihiro Iwasa, Hideki Matsuoka, Hidefumi Takahashi, Shintaro Ishiwata, Yoshinori Okada, Masaki Nakano, Kyoko Ishizaka

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Abstract

Reducing dimensionality can induce profound modifications to the physical properties of a system. In two-dimensional TaS2 and TaSe2, the charge-density wave phase accompanies a Mott transition, thus realizing the strongly correlated insulating state. However, this scenario deviates from TaTe2 due to p–d hybridization, resulting in a substantial contribution of Te 5p at the Fermi level. Here, we show that, differently from the Mott insulating phase of its sister compounds, bilayer TaTe2 hosts a power-law (V-shaped) gap at the Fermi level reminiscent of a Coulomb gap. It suggests the possible role of unscreened long-range Coulomb interactions emerging in lowered dimensions, potentially coupled with a disordered short-range charge-density wave. Our findings reveal the importance of long-range interactions sensitive to interlayer screening, providing another venue for the interplay of complex quantum phenomena in two-dimensional materials.

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分子束外延生长的双层 TaTe2 中尺寸驱动的幂律间隙

降低维度可以对系统的物理性质产生深远的影响。在二维 TaS2 和 TaSe2 中，电荷密度波相伴随着莫特转换，从而实现了强相关绝缘态。然而，由于 p-d 杂化，这种情况与 TaTe2 存在偏差，导致费米级 Te 5p 的大量贡献。在这里，我们展示了不同于其姊妹化合物的莫特绝缘相，双层 TaTe2 在费米水平存在一个幂律（V 型）间隙，让人联想到库仑间隙。这表明在降低维度时可能会出现未屏蔽的长程库仑相互作用，并可能与无序的短程电荷密度波相耦合。我们的发现揭示了对层间屏蔽敏感的长程相互作用的重要性，为研究二维材料中复杂量子现象的相互作用提供了另一个途径。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

APL Materials NANOSCIENCE & NANOTECHNOLOGYMATERIALS SCIE-MATERIALS SCIENCE, MULTIDISCIPLINARY

CiteScore

9.60

自引率

3.30%

发文量

199

审稿时长

2 months

期刊介绍： APL Materials features original, experimental research on significant topical issues within the field of materials science. In order to highlight research at the forefront of materials science, emphasis is given to the quality and timeliness of the work. The journal considers theory or calculation when the work is particularly timely and relevant to applications. In addition to regular articles, the journal also publishes Special Topics, which report on cutting-edge areas in materials science, such as Perovskite Solar Cells, 2D Materials, and Beyond Lithium Ion Batteries.