Evidence of Topological Phase Transition with Excellent Catalytic Activity in the AgCaAs Heusler Alloy: A First-Principles Investigation,The Journal of Physical Chemistry C

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Evidence of Topological Phase Transition with Excellent Catalytic Activity in the AgCaAs Heusler Alloy: A First-Principles Investigation
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2023-07-31 , DOI: 10.1021/acs.jpcc.3c01844
Bhautik R. Dhori ₁ , Darshil Chodvadiya ₁ , Prafulla K. Jha ₁

Affiliation

Topological insulators are centered on the objective that a spin-locked surface state exhibits exceptional spin transport properties with an insulating bulk. In the present work, we predict biaxial strain-induced topological phase transition in the non-centrosymmetric compound AgCaAs, using first-principles calculations. Under ambient conditions, bulk AgCaAs exhibits a trivial nature with an insulating gap; however, on applying biaxial strain the system exhibits Dirac semimetallic behavior, indicating toward topological phase transition. At a 2% biaxial strain, a non-trivial topological phase emerges, which is verified by the orbital inversion across the Fermi level with a massless Dirac cone along the surfaces. Furthermore, by confining the bulk system in one dimension, we obtained a 2D AgCaAs (1T-MoS₂ type) system. The low-dimensional phase exhibits a trivial nature having a 0.48 eV energy gap. Under a moderate tensile strain, the system undergoes a topological phase transition with a 26.2 meV non-trivial energy gap. Such spin–orbit coupling-induced topological phase transition is further confirmed by computing and analyzing the Z2 $Z_{2}$ invariants, surface states, slab band structure, and evolution of Wannier charge centers. In terms of energy application, 2D AgCaAs exhibits excellent catalytic activity toward hydrogen evolution reactions. Investigating the catalytic properties of 2D AgCaAs in their non-trivial state has become a pathway for topological quantum catalysis. The Gibbs free energy for 2D AgCaAs was found to be −0.13 eV and suggests an opportunity for experimentalists to develop a catalyst for energy applications. Our findings deliver new insights into next-generation nano-electronics and better catalysts.

中文翻译：

AgCaAs Heusler 合金中具有优异催化活性的拓扑相变证据：第一性原理研究

拓扑绝缘体的目标是自旋锁定表面态在绝缘体上表现出优异的自旋输运特性。在目前的工作中，我们利用第一性原理计算预测了非中心对称化合物 AgCaAs 中双轴应变诱导的拓扑相变。在环境条件下，块状 AgCaAs 表现出具有绝缘间隙的微不足道的性质；然而，在施加双轴应变时，系统表现出狄拉克半金属行为，表明拓扑相变。在 2% 双轴应变下，出现了一个非平凡的拓扑相，这通过沿表面的无质量狄拉克锥穿过费米能级的轨道反转得到了验证。此外，通过将体系统限制在一维，我们获得了 2D AgCaAs (1T-MoS ₂型）系统。低维相表现出具有 0.48 eV 能隙的平凡性质。在中等拉伸应变下，系统会发生拓扑相变，能隙达到 26.2 meV。通过计算和分析进一步证实了这种自旋轨道耦合引起的拓扑相变Z 2 $Z_{2}$ 不变量、表面态、板条能带结构以及万尼尔电荷中心的演化。在能源应用方面，2D AgCaAs 对析氢反应表现出优异的催化活性。研究非平凡态二维 AgCaAs 的催化性能已成为拓扑量子催化的一条途径。二维 AgCaAs 的吉布斯自由能为 -0.13 eV，这表明实验学家有机会开发能源应用催化剂。我们的研究结果为下一代纳米电子学和更好的催化剂提供了新的见解。

更新日期：2023-07-31

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