Novel pressure-induced topological phase transitions of supercooled liquid and amorphous silicene

NA Huy and LT Nguyen and DLT Nguyen and TQ Truong and L Ong and VV Hoang and GH Nguyen, JOURNAL OF PHYSICS-CONDENSED MATTER, 31, 095403 (2019).

DOI: 10.1088/1361-648X/aaf402

This molecular dynamics (MD) simulation carries a detailed analysis of a pressure-induced structural transition supercooled liquid and amorphous silicene (a-silicene). Low-density models of supercooled liquid and a-silicene containing 10000 atoms are obtained by rapid cooling processes from the melts. Then, an a-silicene model at T = 1000K, a supercooled liquid model at T = 1500K and a liquid silicon model at T = 2000 K have been isothermally compressed step by step up to a high density in order to observe the pressure-induced structural changes. Specifically 'Cairo tiling' pentagonal and square lattices of silicene are discovered in our calculations. Structural properties of those penta-silicene and tetra-silicene models have been carefully analyzed through the radial distribution functions, interatomic distances, bond- angle distributions under high-pressure condition. The dependence of pressure on formation behaviors is calculated via pressure-volume and energy-density relationships. The first order transition from low- density supercooled liquid/amorphous silicene to high-density penta- silicene and continuous transition from low-density liquid to high- density tetra-silicene are discussed. Atomic mechanism and sp(3)/sp(2) hybridization evolution are inspected whereas the role of low-membered ring defects/boundary promises remarkable application and advanced research in future.

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