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arXiv · 2001.01208

Novel Superstructure-Phase Two-Dimensional Material 1$\textit{T}$-VSe$_2$ at High Pressure

Raimundas Sereika·Changyong Park·Curtis Kenney-Benson·Sateesh Bandaru·Niall J. English·Qiangwei Yin·Hechang Lei·Ning Chen·Cheng-Jun Sun·Steve M. Heald·Jichang Ren·Jun Chang·Yang Ding·Ho-kwang Mao
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Abstract

A superstructure can elicit versatile new properties of materials by breaking their original geometrical symmetries. It is an important topic in the layered graphene-like two-dimensional transition-metal dichalcogenides (TMDs), but its origin remains unclear. Using diamond-anvil cell techniques, synchrotron x-ray diffraction, x-ray absorption, and the first-principles calculations, we show that the evolution from the weak Van der Waals bonding to the Heisenberg covalent bonding between layers induces an isostructural transition in quasi-two-dimensional 1$\textit{T}$-type VSe$_2$ at high pressure. Furthermore, our results show that high-pressure induce a novel superstructure at 15.5 GPa, rather than suppress as it would normally, which is unexpected. It is driven by the Fermi surface nesting, enhanced by the pressure-induced distortion. The results suggest that the superstructure not only appears in the two-dimensional structure but also can emerge in the pressure-tuned three-dimensional structure with new symmetry and develop superconductivity.

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Raimundas Sereika, Changyong Park, Curtis Kenney-Benson, Sateesh Bandaru, Niall J. English, Qiangwei Yin, Hechang Lei, Ning Chen, Cheng-Jun Sun, Steve M. Heald, Jichang Ren, Jun Chang, Yang Ding, Ho-kwang Mao. 2020-01-05. Novel Superstructure-Phase Two-Dimensional Material 1$\textit{T}$-VSe$_2$ at High Pressure. https://doi.org/10.1021/acs.jpclett.9b03247

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