npj：二维硼烯氧化物B2O的超导电性—理论解析

海归学者发起的公益学术平台

分享信息，整合资源

交流学术，偶尔风月

最近实验上合成的硼烯单层被证明是优异的二维(2D)超导体，但是由于硼原子的缺电子特性使硼烯中的B-B键不稳定且易被氧化而最终呈现不稳定的特性。人们发现通过在硼烯中嵌入氧原子可以使得结构更加稳定，并表现出不同的物理化学性质。是否2D硼烯氧化物也像硼烯一样表现出优异的超导电性值得被探索，这个问题的解决不仅能扩充二维超导体家族，也能切实促进了相关的实验探索。

来自电子科技大学的周柳江教授和高能物理研究所王保田副研究员等人以2D蜂窝硼烯氧化物B₂O材料为例，结合粒子群优化算法和第一性原理计算，首先证实了体系较高的热稳定性，接着系统地研究了它的电子性质与超导性。结果显示2D B₂O不仅表现出拉克金属态的特性，而且也是一种本征2D超导体，其超导转变温度T_c为10.3K。通过施加双轴应变，发现在面内1%的拉伸应力下，T_c能达到最大值14.7 K。相比大部分二维金属硼基超导体 (0.2-7.8K)，较轻的氧原子的引入，会显著增强体系面外的振动模式，从而最终提高超导温度。在二维体系中通过较轻原子的引入来增强体系电声耦合效应与超导温度的策略，为后续设计更高T_c的2D超导体提供了理论线索。

该文近期发表于npj Computational Materials 6: 94 (2020)，英文标题与摘要如下，点击左下角“阅读原文”可以自由获取论文PDF。

Theoretical dissection of superconductivity in two-dimensional

honeycomb borophene oxide B₂O crystal with a high stability

Luo Yan, Peng-Fei Liu, Hengtao Li, Yong Tang, Junjie He, Xingyong Huang, Bao-Tian Wang  and Liujiang Zhou

Atomically thin borophene has recently been synthesized in experiment, significantly enriching the boron chemistry and broadening the family oftwo-dimensional (2D) materials. Recently, oxides of 2D materials have been widely investigated for next-generation electronicdevices. Based on the first-principles calculations, we predict the existence of the superconductivity in honeycomb borophene oxide (B₂O), which possesses a high stability and couldbe potentially prepared by intrinsically incorporating oxygen into the recently synthesized borophene. The mechanical, electronic, phonon properties, as well aselectron-phonon coupling of metallic B₂O monolayer have been systematically scrutinized. Within the framework of the Bardeen-Cooper-Schrieffer theory framework, the B₂O monolayer exhibits an intrinsic superconducting feature with a superconducting transition temperature (Tc) of ∼10.3 K, higher than many 2D borides (0.2-7.8 K). Further, strain can be utilized to tune the superconductivity with the optimal Tc of 14.7 K under a tensile strain of 1%. The superconducting trait is mainly originated from the out-of-plane soft-mode vibrations of system, which are significantly enhanced via the light O atoms’ incorporation compared to other 2D metal boride superconductors. This strategy would open a door to design 2D superconducting structures via the participation of light elements. We believe our findings greatly bloom the 2D superconducting family and pave the way for future nanoelectronics. 

扩展阅读

 

本文系网易新闻·网易号“各有态度”特色内容

媒体转载联系授权请看下方