A pressure-induced high-pressure metallic GeTe phase.
Lamei Zhao1, Xinran Zhang1, Biao Wan1
1Key Laboratory of Material Physics of Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China.
The Journal of Chemical Physics
|April 8, 2023
Summary
Researchers predicted a new Cmca phase for germanium telluride (GeTe) under high pressure. This phase exhibits metallic properties and superconductivity, advancing our understanding of GeTe
Area of Science:
- Materials Science
- Condensed Matter Physics
- Computational Materials Science
Background:
- Germanium telluride (GeTe) is a crucial phase-change material with complex high-pressure behavior.
- Identifying high-pressure GeTe crystal structures is challenging due to phase coexistence and reversible transitions.
- Experimental characterizations alone provide limited insights into GeTe's high-pressure structural evolution.
Purpose of the Study:
- To elucidate the unclear phase transitions of GeTe under high pressure.
- To predict and characterize new high-pressure phases of GeTe using computational methods.
- To understand the structural evolution and physical properties of GeTe at extreme pressures.
Main Methods:
- Utilized the CALYPSO method for predicting new crystal structures under pressure.
- Performed first-principles calculations to determine energetic favorability and structural stability.
- Calculated electron-phonon coupling to assess superconductivity and simulated X-ray diffraction patterns.
Main Results:
- Predicted a new orthorhombic Cmca GeTe phase as the most stable between approximately 30 and 38.5 GPa.
- The Cmca phase displays strong metallic properties, evidenced by high density of states and electron delocalization.
- Calculations indicate superconductivity in the Cmca phase below 4.2 K at 35 GPa, with potential coexistence with the Pnma-boat phase.
Conclusions:
- The newly predicted Cmca phase updates the known high-pressure phase transition sequence for GeTe.
- The study reveals significant metallic and superconductive properties of GeTe under high pressure.
- Findings enhance the understanding of high-pressure structural evolution and properties in GeTe and related IV-VI semiconductors.
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