单层
单斜晶系
相变
拉曼光谱
材料科学
化学物理
兴奋剂
相(物质)
六角相
凝聚态物理
Crystal(编程语言)
晶体结构
结晶学
纳米技术
化学
光电子学
光学
物理
有机化学
程序设计语言
计算机科学
作者
Ying Wang,Jun Xiao,Hanyu Zhu,Yao Li,Yousif Alsaid,King Yan Fong,Yao Zhou,Siqi Wang,Wu Shi,Yuan Wang,Alex Zettl,Evan J. Reed,Xiang Zhang
出处
期刊:Nature
[Springer Nature]
日期:2017-10-01
卷期号:550 (7677): 487-491
被引量:572
摘要
Monolayers of transition-metal dichalcogenides (TMDs) exhibit numerous crystal phases with distinct structures, symmetries and physical properties. Exploring the physics of transitions between these different structural phases in two dimensions may provide a means of switching material properties, with implications for potential applications. Structural phase transitions in TMDs have so far been induced by thermal or chemical means; purely electrostatic control over crystal phases through electrostatic doping was recently proposed as a theoretical possibility, but has not yet been realized. Here we report the experimental demonstration of an electrostatic-doping-driven phase transition between the hexagonal and monoclinic phases of monolayer molybdenum ditelluride (MoTe2). We find that the phase transition shows a hysteretic loop in Raman spectra, and can be reversed by increasing or decreasing the gate voltage. We also combine second-harmonic generation spectroscopy with polarization-resolved Raman spectroscopy to show that the induced monoclinic phase preserves the crystal orientation of the original hexagonal phase. Moreover, this structural phase transition occurs simultaneously across the whole sample. This electrostatic-doping control of structural phase transition opens up new possibilities for developing phase-change devices based on atomically thin membranes.
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