Structural evolution and phase transition mechanism of $$hbox {MoSe}_2$$ MoSe 2 under high pressure

Structural evolution and phase transition mechanism of $$hbox {MoSe}_2$$ MoSe 2 under high pressure

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Abstract $$hbox {MoSe}_2$$ MoSe 2 is a layered transition-metal dichalcogenide (TMD) apunisw2 with outstanding electronic and optical properties, which is widely used in field-effect transistor (FET).Here the structural evolution and phase transition of $$hbox {MoSe}_2$$ MoSe 2 under high pressure are systematically studied by CALYPSO structural search method and first-principles calculations.The structural evolutions of $$hbox {MoSe}_2$$ MoSe 2 show that the ground state structure under ambient pressure is the experimentally observed P6 $$_3$$ 3 /mmc phase, which transfers to R3m phase at 1.9 GPa.The trigonal R3m phase of $$hbox {MoSe}_2$$ MoSe 2 is stable up to 72.

1 GPa, then, it transforms into a new P6 $$_3$$ 3 /mmc phase with different atomic coordinates of Se atoms.This phase is extremely robust under ultrahigh pressure and finally changes to another trigonal R-3m phase under 491.1 GPa.The elastic constants and phonon dispersion curves indicate that the ambient pressure phase and three new high-pressure phases are all stable.The electronic band structure and projected density cent dyyni of states analyses reveal a pressure induced semiconducting to metallic transition under 72.

1 GPa.These results offer a detailed structural evolution and phase diagram of $$hbox {MoSe}_2$$ MoSe 2 under high pressure, which may also provide insights for exploration other TMDs under ultrahigh pressure.