Pressure-driven phase transition induces simultaneous negative photoconductivity and superconductivity
Phase diagrams as a function of pressure during compression and decompression functions of carrier concentration NE superconducting and photoconductive PBSE0.5TE0.5. Credit: Wang Pei
A research team led by Professor Wang Xianlong and Dr. Wang Pei of the Institute for Physical Sciences at the Chinese Academy of Sciences discovered the simultaneous negative photoconductivity (NPC) and superconductivity of PBSE0.5TE0.5 due to the transition of pressure-induced structures. did. . This study is published in Advanced Materials.
NPC is a unique phenomenon in which the conductivity of a material is reduced due to the trapping of charge carriers in localized states, reducing the number of free carriers, which is more common in positive photoconductivity (PPC). It’s against the behavior.
NPCs are of great promise in next-generation semiconductor Optoelectronics, and their application potential has recently reached beyond photodetection, but this phenomenon has been rarely reported. In particular, simultaneous NPCs and superconductivity are rarely observed at high pressures, due to the lack of in situ experimental measurement facilities.
In this study, the team systematically investigated the response of PBSE0.5TE0.5 to pressure modulation under visible light and cold stimulation using a self-developed facility. Through a detailed experimental and theoretical approach, researchers investigated how changes in the crystal structure and electronic structure of the material influenced both the properties of photoconduits and superconducting.
They found that pressure-driven PPC–NPC transitions arise from a strong nonequilibrium distribution of excitation carriers. This is due to enhanced electron-phonon interactions due to photothermal effects that reduce electron concentration and mobility.
Density functional theory (DFT) theory calculations dramatically enhanced p-P and S-P hybridization lead to enhanced electron-phonon interactions at the Fermi level, resulting in the transition from semiconductor to aspirator. It has been proven to be promoted. Structure-dependent superconductivity and NPCs are switched by electron-phonon interactions via pressure under illumination or cooling.
This study sheds light on the origins of superconducting and photoconductive transitions in lead chalcogenide versatile materials.
Details: Dongxuan Han et al, PBSE0.5TE0.5, Simultaneous pressure-induced superconductivity and photoconductive transitions in advanced materials (2024). doi:10.1002/adma.202417597
Provided by the Chinese Academy of Sciences
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