Two dense semiconducting phases of LiInTe2 under high pressure

Two novel dense phases with hexagonal P63mc and trigonal space symmetries were firstly identified for the typical Li-based ternary chalcogenide LiInTe2 under high pressure, using the advanced particle swarm methodology for crystal structure search. Pressure-induced structure transition from ambient-pressure chalcopyrite to hexagonal P63mc structure was determined above 0.9 GPa, while a competitively metastable structure was also discovered. A large volume drop of 19.1% demonstrated the first-order phase transition of → P63mc. In contrast to phase with a direct band gap, both P63mc and phases display a much narrower indirect band gap of 0.376 eV and 0.531 eV, stemming from the increase coordination number of Li/In from 4 to 6 and the resulting modification of atomic chemical bonding. Strong ionic bonding feature in these high-pressure structures was further revealed through a topological analysis of charge density. Finally, compared to ambient phase, their more excellent optical absorption efficiencies in the visible photon energy range were determined.