Correlation of Valence electron structure and properties of monolayer graphene and MX2 (M=Mo, W; X=S, Se, Te): Empirical Electron Theory (EET) investigation

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY

Physica E-low-dimensional Systems & Nanostructures Pub Date : 2024-10-08 DOI:10.1016/j.physe.2024.116124

Xinze Wang, Yongquan Guo, Boyang Li, Yichen Feng, Wei Tang

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引用次数: 0

Abstract

The atomically thin layers of transition-metal dichalcogenide (TMDC) materials have garnered considerable attention due to their exceptional electrical, optical, mechanical, and thermal properties. Hence, it is important to investigate the mechanism of their excellent properties. In this paper, the study is focused on the correlation between valence electron structures (VESs) and mechanical as well as thermal properties of graphene and MX₂ (M = Mo, W; X = S, Se, Te) for revealing their essential mechanisms of properties with an empirical electron theory (EET). A model of Young's modulus is built for the monolayer graphene and MX₂ (M = Mo, W; X = S, Se, Te) based on the VES, which has been verified by the observed ones of elements in the 4th to 6th periods in the periodic table of elements. The calculated bond lengths and mechanical and thermal properties of graphene and MX₂ are in good agreement with experimental ones. The study reveals that the thermal and mechanical properties of MX₂ strongly depend on their valence electron structures. It shows that the melting point, cohesive energy, thermal conductivity, and Young's modulus are modulated by covalence electron pair n_A, the averaged covalence electron per atom n_c/atom, covalence electron pair n_A and linear density of covalent electron on the strongest bond ρ_l, respectively. The study helps explain the thermal and mechanical properties of two-dimensional (2D) materials and also supplies a reference for their design with high performance by modulating their valence electron structures.

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单层石墨烯和 MX2（M=Mo、W；X=S、Se、Te）的价电子结构和性质的相关性：经验电子理论 (EET) 研究

过渡金属二卤化物（TMDC）材料的原子薄层因其卓越的电学、光学、机械和热学特性而备受关注。因此，研究其优异特性的机理非常重要。本文的研究重点是石墨烯和 MX2（M = Mo、W；X = S、Se、Te）的价电子结构（VES）与机械性能和热性能之间的相关性，从而利用经验电子理论（EET）揭示其性能的本质机理。基于 VES，建立了单层石墨烯和 MX2（M = Mo、W；X = S、Se、Te）的杨氏模量模型，并通过观测元素周期表中第 4 至第 6 周期元素的杨氏模量进行了验证。计算得出的石墨烯和 MX2 的键长、机械性能和热性能与实验结果十分吻合。研究表明，MX2 的热性能和机械性能在很大程度上取决于其价电子结构。研究表明，熔点、内聚能、热导率和杨氏模量分别受共价电子对 nA、每个原子的平均共价电子 nc/原子、共价电子对 nA 和最强键上共价电子的线性密度 ρl 的调节。这项研究有助于解释二维（2D）材料的热性能和机械性能，也为通过调节其价电子结构设计高性能材料提供了参考。

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

Physica E-low-dimensional Systems & Nanostructures 物理-纳米科技

CiteScore

7.30

自引率

6.10%

发文量

356

审稿时长

65 days

期刊介绍： Physica E: Low-dimensional systems and nanostructures contains papers and invited review articles on the fundamental and applied aspects of physics in low-dimensional electron systems, in semiconductor heterostructures, oxide interfaces, quantum wells and superlattices, quantum wires and dots, novel quantum states of matter such as topological insulators, and Weyl semimetals. Both theoretical and experimental contributions are invited. Topics suitable for publication in this journal include spin related phenomena, optical and transport properties, many-body effects, integer and fractional quantum Hall effects, quantum spin Hall effect, single electron effects and devices, Majorana fermions, and other novel phenomena. Keywords: • topological insulators/superconductors, majorana fermions, Wyel semimetals; • quantum and neuromorphic computing/quantum information physics and devices based on low dimensional systems; • layered superconductivity, low dimensional systems with superconducting proximity effect; • 2D materials such as transition metal dichalcogenides; • oxide heterostructures including ZnO, SrTiO3 etc; • carbon nanostructures (graphene, carbon nanotubes, diamond NV center, etc.) • quantum wells and superlattices; • quantum Hall effect, quantum spin Hall effect, quantum anomalous Hall effect; • optical- and phonons-related phenomena; • magnetic-semiconductor structures; • charge/spin-, magnon-, skyrmion-, Cooper pair- and majorana fermion- transport and tunneling; • ultra-fast nonlinear optical phenomena; • novel devices and applications (such as high performance sensor, solar cell, etc); • novel growth and fabrication techniques for nanostructures