Sattigeri Raghottam M, Jha Prafulla K
Department of Physics, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara-390002, Gujarat, India.
J Phys Condens Matter. 2021 Nov 30;34(8). doi: 10.1088/1361-648X/ac3a47.
The discovery of group IV and V elemental xene's with topologically non-trivial characters in their honeycomb lattice structure (HLS) has led to extensive efforts in realising analogous behaviour in group VI elemental monolayers. Theoretically; it was concluded that, group VI elemental monolayers cannot exist in HLS. However, some recent experimental evidence suggests that group VI elemental monolayers can be realised in HLS. In this letter, we report HLS of group VI elemental monolayer (such as, tellurene) can be realised to be dynamically stable when functionzalised with oxygen. The functionalization leads to, peculiar orbital filtering effects and broken spatial inversion symmetry which gives rise to the non-trivial topological character. The exotic quantum behaviour of this system is characterized by, spin-orbit coupling induced large-gap (≈0.36 eV) with isolated Dirac cone along the edges indicating potential room temperature spin-transport applications. Further investigations of spin Hall conductivity and the Berry curvatures unravel high conductivity as compared to previously explored xene's alongside the potential valley Hall effects. The non-trivial topological character is quantified in terms of theZ2invariant as= 1 and Chern number= 1. Also, for practical purposes, we report that,BN/TeO/BN quantum-wells can be strain engineered to realize a sizeable non-trivial gap (≈0.11 eV). We finally conclude that, functionalization of group VI elemental monolayer with oxygen gives rise to, exotic quantum properties which are robust against surface oxidation and degradations while providing viable electronic degrees of freedom for spintronic/valleytronic applications.
在其蜂窝晶格结构（HLS）中发现具有拓扑非平凡特性的IV族和V族元素烯，促使人们为在VI族元素单层中实现类似行为做出了广泛努力。从理论上讲，得出的结论是，VI族元素单层不能以HLS形式存在。然而，最近的一些实验证据表明，VI族元素单层可以在HLS中实现。在这封信中，我们报告了VI族元素单层（如碲烯）的HLS在用氧官能化时可以实现动态稳定。这种官能化导致了奇特的轨道过滤效应和空间反演对称性的破坏，从而产生了非平凡的拓扑特性。该系统的奇异量子行为的特征是，自旋轨道耦合诱导出大的能隙（约0.36电子伏特），沿边缘有孤立的狄拉克锥，这表明有潜在的室温自旋输运应用。对自旋霍尔电导率和贝里曲率的进一步研究揭示，与之前探索的烯相比，其具有高电导率以及潜在的谷霍尔效应。非平凡的拓扑特性通过Z2不变量等于1和陈数等于1来量化。此外，出于实际目的，我们报告，BN/TeO/BN量子阱可以通过应变工程来实现可观的非平凡能隙（约0.11电子伏特）。我们最终得出结论，用氧对VI族元素单层进行官能化会产生奇异的量子特性，这些特性对表面氧化和降解具有鲁棒性，同时为自旋电子学/谷电子学应用提供了可行的电子自由度。
