等结构
拉曼光谱
凝聚态物理
半金属
相变
半导体
密度泛函理论
费米能级
拉曼散射
材料科学
化学
电子
物理
晶体结构
计算化学
光学
量子力学
结晶学
带隙
光电子学
作者
Achintya Bera,Anjali Singh,D. V. S. Muthu,Umesh V. Waghmare,A. K. Sood
标识
DOI:10.1088/1361-648x/aa55a1
摘要
High pressure Raman spectroscopy of bulk 2H-MoTe2 up to ∼29 GPa is shown to reveal two phase transitions (at ∼6 and 16.5 GPa), which are analyzed using first-principles density functional theoretical calculations. The transition at 6 GPa is marked by changes in the pressure coefficients of A1g and Raman mode frequencies as well as in their relative intensity. Our calculations show that this is an isostructural semiconductor to a semimetal transition. The transition at ∼16.5 GPa is identified with the changes in linewidths of the Raman modes as well as in the pressure coefficients of their frequencies. Our theoretical analysis clearly shows that the structure remains the same up to 30 GPa. However, the topology of the Fermi-surface evolves as a function of pressure, and abrupt appearance of electron and hole pockets at GPa marks a Lifshitz transition.
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