摘要
拓扑半金属,作为一种独特的拓扑电子态,近年来因其固有的拓扑特性和潜在的器件应用而备受研究关注.体-边界对应是拓扑半金属的一个关键特征,这意味着如果在体相中存在非平庸的能带拓扑,那么在表面会存在受拓扑保护导电状态,即拓扑表面态(topological surface state,TSS).这一特征使其在电催化研究领域备受关注.本文采用第一性原理计算手段研究了AlB_(2)材料的拓扑性质,并构建(010)表面A1端面和B端面平板模型,计算得到了TSS的位置.研究了AlB_(2)表面吸附特性,发现Al端面氢吸附吉布斯自由能(ΔG_(H*))仅为-0.031 eV,相较于商业电催化析氢(hydrogen evolution reaction,HER)催化剂Pt的-0.08 eV更接近于0,展现出了优异的HER性能.观察了AlB_(2)表面吸附H,OH和H_(2)O后TSS的变化,发现当H吸附时TSS变化最显著,其次是OH吸附,H_(2)O因其电中性和弱的表面吸附对TSS的影响很微弱.并且在吸附前后,由于受拓扑保护TSS依旧存在,仅是能量发生了改变,证实了其在环境中的稳定性.本工作研究结果为不同吸附物对AlB_(2)的TSS的影响提供了系统的认识,为今后相关领域的理论和实验研究铺平了道路,也为拓扑材料的实际应用提供了理论支撑.
Topological semimetals have aroused great research interest due to their intrinsic topological physics and potential applications in devices.A key feature for all topological materials is the so-called bulk-boundary correspondence,which means that if there is non-trivial band topology in the bulk,then we can expect unique topologically protected conducting states in the surface,i.e.the topological surface state(TSS).Previously,the studies of the surface states of topological materials mainly focused on the pristine surfaces,while the topological nodal line semimetal surface states with adsorbates are rarely systematically studied.In this paper,the topological properties of the topological semimetal AlB_(2) are studied by first-principles calculations,and the TSS position is calculated by constructing the Al-and B-terminated slab models.Observing the topological surface state,it is found that the drumhead-like TSS connects two Dirac nodes with no energy gaps on the node line,and the TSS of the Al end-terminated slab has a smaller energy dispersion than that of the B-terminated slab.The adsorption characteristics of AlB_(2)(010)surface are studied,and it is found that the Gibbs free energy(ΔG_(H*))for hydrogen adsorption on the surface of Al is only-0.031 eV,demonstrating excellent hydrogen evolution reaction(HER)performance.The changes of TSS after H,OH and H_(2)O are adsorbed on the surface of AlB_(2) in aqueous solution environment are observed.The TSS change is the most significant when H is adsorbed,followed by OH adsorption.And the influence of H_(2)O on TSS due to its electrical neutrality and weak surface adsorption is very weak.Before and after adsorption,because the topology protection TSS still exists,only the energy changes,which confirms its robustness in the environment.The results of this work provide a systematic understanding of the effects of different adsorbents on the TSS of AlB_(2),paving the way for future theoretical and experimental research in related fields,and alsopresent theoretical sup
作者
朱庞栋
王长昊
王如志
Zhu Pang-Dong;Wang Chang-Hao;Wang Ru-Zhi(Key Laboratory of Advanced Functional Materials of Education Ministry of China,Institute of New Energy Materials and College of Materials Science and Engineering,Beijing University of Technology,Beijing 100124,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第12期350-358,共9页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11804012)
北京工业大学城市碳中性科技创新基金(批准号:048000514123695)资助的课题。
关键词
拓扑半金属
拓扑表面态
表面吸附
topological semimetal
topological surface state
surface adsorption
