Unraveling a novel ferroelectric GeSe phase and its transformation into a topological crystalline insulator under high pressure

• DOI: 10.1038/s41427-018-0081-y
• Publication Date: 2018-09-07T13:35:01Z
• Authors: Hulei Yu; Dexiang Gao; Xiancheng Wang; Xueyan Du; Xiaohuan Lin; Wenhan Guo; Ruqiang Zou; Changqing Jin; Kuo Li; Yue Chen
• Keywords: Hydrostatic pressure; Selenide; Diamond anvil cell; Ambient pressure; Topological insulator

Germanium selenide is a promising material for electronic, photovoltaic, and thermoelectric applications; however, structural phase transitions of GeSe under pressure are controversial. Combining evolutionary algorithms, density functional theory, tight-binding method, laser-heated diamond anvil cell experiments, pressure-induced thoroughly investigated. Two novel intermediate phases predicted to exist in between the well-known α-GeSe recently discovered β-GeSe high pressure. found transform into rhombohedral crystal structure with space group R3m at low hydrostatic The exhibits robust ferroelectricity analogous GeTe. By further increasing approximately 6 GPa, rock-salt structure, becoming 3D topological crystalline insulator an inverted band structure. newly high-pressure greatly enrich our knowledge IV–VI compounds. atoms germanium can adopt more configurations than previously thought according study by researchers China. A change, rearrangement solid from one another, radically alter material's properties. Such change be induced exposing matter Kuo Li Center High Pressure Science Technology Advanced Research Beijing, Yue Chen University Hong Kong, their co-workers have combined multiple computational experimental techniques identify selenide, useful energy conversion. Recently called was addition common low-pressure phase. predict two pressure, each its own distinctive electrical Pressure-induced investigated theory experiment. new in-between pressures. It that transforms Laser-heated DAC experiments been conducted provide evidence on existence ( $$Fm\bar 3m$$ ) become insulator.