Bera Achintya, Singh Anjali, Gupta Satyendra Nath, Glazyrin K, Muthu D V S, Waghmare U V, Sood A K
Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
Center for Study of Science, Technology and Policy, Bangalore-560094, India.
J Phys Condens Matter. 2021 Feb 10;33(6):065402. doi: 10.1088/1361-648X/abaeac.
Synchrotron x-ray diffraction measurements on powder 2H-MoTe (P6/mmc) up to ∼46 GPa have been performed along with first-principles based density functional theoretical analysis to probe the isostructural transition in low pressure regime and two electronic topological transitions (ETT) of Lifshitz-type in high pressure regime. The low pressure isostructural transition at ∼7 GPa is associated with the lattice parameter ratio c/a anomaly and the change in the compressibility of individual layers. The pressure dependence of the volume by linearizing the Birch-Murnaghan equation of state as a function of Eulerian strain shows a clear change of the bulk modulus at the ETT pressure of ∼20 GPa. The minimum of c/a ratio around 32 GPa is associated with the change in topology of electron pockets marked as second ETT of Lifshitz-type. We do not observe any structural transition up to the maximum applied pressure of ∼46 GPa under quasi-hydrostatic condition.
对粉末状2H-MoTe（P6/mmc）进行了高达约46 GPa的同步加速器X射线衍射测量，并结合基于第一性原理的密度泛函理论分析，以探究低压区的同结构转变和高压区的两种Lifshitz型电子拓扑转变（ETT）。约7 GPa处的低压同结构转变与晶格参数比c/a异常以及各层压缩性的变化有关。通过将Birch-Murnaghan状态方程线性化为欧拉应变的函数，体积的压力依赖性表明在约20 GPa的ETT压力下，体积模量有明显变化。约32 GPa处c/a比的最小值与标记为Lifshitz型第二ETT的电子口袋拓扑结构变化有关。在准静水压条件下，直至约46 GPa的最大施加压力，我们未观察到任何结构转变。
