arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1804.04575cond-mat.mtrl-scicond-mat.dis-nncond-mat.mes-hall
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单层MoS $_2$的1 $T'$和2 PDMATHAAB相中的点缺陷:比较第一性原理研究

Point defects in the 1$T'$ and 2$H$ phases of single-layer MoS$_2$: A comparative first-principles study

Michele Pizzochero, Oleg V. Yazyev

摘要:

由于层状过渡金属二硫属化物的亚稳1 $T'$相的电子性质、可能的拓扑电子相和催化活性,最近引起了相当大的兴趣。我们报告了一个全面的理论研究的1 $T'$结晶相的单层二硫化钼(1 $T'$ -MoS $_2$)的本征点缺陷,并提供了比较充分研究的半导体2 $H$相。基于密度泛函理论计算,我们探索了大量的空位、吸附原子和反位缺陷的组态,分析了它们的原子结构、热力学稳定性、电子和磁性。出现的图像表明,在热力学平衡下,1 $T'$ -MoS $_2$比2 $H$相更倾向于容纳晶格缺陷。更具体地说,我们的研究结果表明,更接近Mo原子平面的S原子是最具反应性的位点。与2 $H$相类似,1 $T'$ -MoS $_2$中很可能出现S空位和吸附原子,而Mo吸附原子和反位诱导局部磁矩。与2 $H$相相反,由于在降低缺陷形成能量中起主要作用的结构弛豫,1 $T'$ -MoS $_2$中的Mo空位预期为丰富的缺陷。总体而言,我们的研究预测,1 $T'$ -MoS $_2$的高质量薄片的实现应该在非常小心的实验室条件下进行,但同时可以利用容易的缺陷引入来定制该多晶型物的物理和化学性质。

英文摘要:

The metastable 1$T'$ phase of layered transition metal dichalcogenides has recently attracted considerable interest due to electronic properties, possible topological electronic phases and catalytic activity. We report a comprehensive theoretical investigation of intrinsic point defects in the 1$T'$ crystalline phase of single-layer molybdenum disulfide (1$T'$-MoS$_2$), and provide comparison to the well-studied semiconducting 2$H$ phase. Based on density functional theory calculations, we explore a large number of configurations of vacancy, adatom and antisite defects and analyse their atomic structure, thermodynamic stability, electronic and magnetic properties. The emerging picture suggests that, under thermodynamic equilibrium, 1$T'$-MoS$_2$ is more prone to hosting lattice imperfections than the 2$H$ phase. More specifically, our findings reveal that the S atoms that are closer to the Mo atomic plane are the most reactive sites. Similarly to the 2$H$ phase, S vacancies and adatoms in 1$T'$-MoS$_2$ are very likely to occur while Mo adatoms and antisites induce local magnetic moments. Contrary to the 2$H$ phase, Mo vacancies in 1$T'$-MoS$_2$ are expected to be an abundant defect due to the structural relaxation that plays a major role in lowering the defect formation energy. Overall, our study predicts that the realization of high-quality flakes of 1$T'$-MoS$_2$ should be carried out under very careful laboratory conditions but at the same time the facile defects introduction can be exploited to tailor physical and chemical properties of this polymorph.

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。

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