在XB2 (X = Sc, Ti, V, Cr, 和 Tc) 中进行结构搜索和超导体发现
Jingjing Meng1, Pengyu Zheng1, Yiran Peng1
1Department of Physics, Center for Advanced Quantum Studies, Beijing Normal University Beijing 100875 China yinzhiping@bnu.edu.cn.
RSC advances
|April 3, 2024
概括
新的高压研究揭示了二化物 (CrB2) 和技术二化物 (TcB2) 分别在26.0K和23.5K的超导性. 这些发现提供了对过渡金属化物中超导机制的见解.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 固态化学 固态化学
背景情况:
- 二 (MgB2) 是一个众所周知的超导体,但了解相关过渡金属化物中的超导性需要进一步研究.
- 在高压下探索新型超导材料对于发现新的现象和应用至关重要.
研究的目的:
- 在高压下研究XB2化合物 (X = Sc,Ti,V,Cr,Tc) 的晶体结构和超导特性.
- 确定潜在的新型超导体,并阐明这些材料中超导的基本机制.
主要方法:
- 对高达100GPa的XB2化合物进行了广泛的结构搜索.
- 密度函数理论 (DFT) 的计算用于确定度,动态稳定性和电子-声声合 (EPC).
- 超导过渡温度 (Tc) 为动态稳定相计算.
主要成果:
- 发现XB2化合物的最低度结构与MgB2.2具有相同的空间组 (P6/mm).
- ScB2,TiB2和VB2在环境压力下是动态稳定的,但不是超导体.
- 在108GPa时,CrB2变得动态稳定,在26.0K时表现出超导性.
- 在9GPa时,TcB2变得动态稳定,在20GPa时,在23.5K时表现出超导性.
- 发现CrB2和TcB2在热力学上是稳定的,这表明合成的潜力.
结论:
- 在特定的压力条件下,CrB2和TcB2被预测为超导体.
- 过渡金属原子 (Cr/Tc) 在CrB2/Tcb2.2中显著影响软音声模式,EPC和超导.
- 这与MgB2形成鲜明对比,其中振动主导了EPC,丰富了对过渡金属化物超导性的理解.
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