Phase transition in two-dimensional tellurene under mechanical strain modulation
Phase transition in two-dimensional tellurene under mechanical strain modulation
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DOI：
10.1016/j.nanoen.2019.01.040
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发表时间：
2019-04
期刊：
影响因子：
17.6
通讯作者：
Yuan Xiang;Shengjie Gao;Rong-guang Xu;Wenzhuo Wu;Y. Leng
中科院分区：
文献类型：
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作者：
Yuan Xiang;Shengjie Gao;Rong-guang Xu;Wenzhuo Wu;Y. Leng
我们基于密度泛函理论(DFT)对二维碲的不同相态进行了计算模拟。这些相根据它们的特征空间群和对称元素进行了分类。文中还说明了这些相与块体晶体碲结构的关系。我们的具体兴趣包括不同相的力学性质计算以及它们之间可能的相变。模拟结果表明，由于不同的原子键和弛豫结构，这些二维Te相具有非常不同的弹性模量。此外，面内压缩有利于α→β相变，而面内拉伸应变使α相比β相更稳定。然而，根据面内应变方向，两相之间的能量差与热能KT相当，甚至比热能T小得多。我们发现，沿着链方向的拉伸应变进一步增加，超过一个临界值，大约12%，可能导致α→γ相变。当拉伸应变大于15%时，γ相比α相更稳定，相变能垒进一步降低。
We carry out computational simulations based on density functional theory (DFT) to investigate different phases of two-dimensional (2-D) tellurene. These phases are classified by their characteristic space groups and symmetry elements. Correlations of these phases to the bulk crystalline tellurium structure are also illustrated. Our specific interests include mechanical property calculations for different phases and the possible phase transitions between them. Simulation results show that these 2-D Te phases have very different elastic moduli due to their different atomic bonding and relaxed structures. Moreover, compression along the in-plane directions facilitates the α → β phase transition, while in-plane tensile strains always make the α-phase more stable than the β-phase. However, the energy difference between the two phases is comparable to or even much smaller than the thermal energykT, depending on the in-plane strain direction. We find that further increase of the tensile strain along the chain direction beyond a critical value, ca. 12%, may lead to a possible α → γ phase transition. As the tensile strain is above 15%, the γ-phase will be more stable than the α-phase, accompanied by a further reduced transition energy barrier.