Motivated by the recent experimental exfoliation of tellurium thin film, and the amazing physical and chemical properties of various theoretically tellurene allotropes, we design a novel and stable pentagonal structure of tellurene (SP-type Te), and make a detailed comparison with other possible Te allotropes, related to their mechanical, electronic and thermoelectric properties. SP-type Te shows the higher expandability than other Te allotropes, due to its lower layer modulus and Young’s modulus. More interestingly its Poisson’s ratio along x (y) direction is unusually negative ($~$ −0.01) which can be further decreased by applying coaxial strain. Three-layers SP-type Te can turn into a topological insulator (TI) with a nontrivial band gap $~$ 0.03 eV when uniaxial compressional strain ${\sigma }_x$ = −7$\%$. Moreover the higher the number of layers in SP-type Te, the lower ${\sigma }_x$ inducing its topological transition requires. At room temperature, lattice thermal conductivity $k_L$ of SP-type Te is the lowest in all Te allotropes, and meanwhile its peak ZT for n-type doping even can reach up to 2.84. Thus if SP-type Te can be synthesized in future, these extraordinary properties would promote it with great potential in designing low-dimensional mechanical, spintronic and thermoelectric devices.

基于最近碲薄膜的实验性剥离以及各种理论上的碲同素异形体惊人的物理和化学性质，我们设计了一种新颖稳定的碲（SP型Te）五边形结构，并与其他可能的Te进行了详细的比较。同素异形体，与它们的机械，电子和热电性质有关。SP型Te由于其较低的层模量和杨氏模量而显示出比其他Te同素异形体更高的可膨胀性。更有趣的是，其沿x（y）方向的泊松比通常为负（$〜$-0.01），可以通过施加同轴应变来进一步降低。三层SP型Te可以转变为带隙很小的拓扑绝缘体（TI）$〜$ 单轴压缩应变为0.03 eV ${\sigma }_X$ = −7$％$。此外，SP型Te的层数越高，则层数越低${\sigma }_X$诱导其拓扑转换。在室温下，晶格热导率${ķ}_{\mathrm{大号}}$SP型Te的Te在所有同素异形体中最低，同时其n型掺杂的峰值ZT甚至可以达到2.84。因此，如果将来可以合成SP型Te，那么这些非凡的性能将使其具有很大的潜力，可用于设计低尺寸的机械，自旋电子和热电器件。