On the mechanism for the 2D phase transition in freestanding group-IV monochalcogenide monolayers
ORAL
Abstract
Group-IV monochalcogenides monolayers MX (M=Ge,Sn ; X=S,Se) are low-dimensional semiconductors which exhibit significant piezoelectric and ferroelectric responses. Monochalcogenide monolayers undergo a structural phase transition from a rectangular unit cell to a square unit cell at a critical temperature. There exist two intriguing descriptions of this behavior: (1) a Landau-Ginzburg effective model and (2) a description of the order-disorder transition based on ab initio molecular dynamics. We explore the phase transition by examining the softening of the phonon modes of SnSe as a function of temperature, in order to shed light on the possible physical mechanism underpinning the transition.
*This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Early Career Award DE-SC0016139. Calculations were performed at Trestles, funded by the National Science Foundation, the Arkansas Economic Development Commission, and the U of A Office of the Vice Provost for Research and Innovation.
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Presenters
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John Villanova
- University of Arkansas
- Physics, University of Arkansas