Variation of topological surface states of nodal line semimetal MgB2 resulting from adsorption of hydrogen, hydroxide, and water molecules,Physical Chemistry Chemical Physics

当前位置： X-MOL 学术 › Phys. Chem. Chem. Phys. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Variation of topological surface states of nodal line semimetal MgB2 resulting from adsorption of hydrogen, hydroxide, and water molecules
Physical Chemistry Chemical Physics ( IF 2.9 ) Pub Date : 2024-09-09 , DOI: 10.1039/d4cp02362e
Pangdong Zhu ₁ , Kun Bu ₂ , Ruzhi Wang ₁ , Changhao Wang ₁

Affiliation

Topological semimetals have garnered significant interest due to their intrinsic topological physics and potential applications in devices. A crucial feature shared by all topological materials is the bulk-boundary correspondence, indicating the presence of unique topologically protected conducting states at the edges when non-trivial band topology exists in the bulk. Previous studies on surface states of topological materials predominantly focused on pristine surfaces, leaving the exploration of surface states in topological semimetals with adsorbates relatively uncharted. This work, based on ab initio calculations, examines variations in the topological surface states of MgB₂, a well-known conventional superconductor and topological nodal line semimetal. We employ a thick slab model with Mg/B atoms as surface terminations to simulate its topological surface states. Subsequently, we investigate the adsorption of hydrogen (H), hydroxide (OH), and water (H₂O) on the surface slabs to observe changes in the surface states. The pristine slab model gives the drumhead-like surface states inside the surface projected nodal lines, while the topological surface states change differently after adsorbing H, OH, and H₂O, which can be understood systematically by combining the surface adsorption Gibbs free energy ΔG, surface terminations, and surface charge density distributions. Especially, our findings suggest that the Bader charge transfer value of surface atoms providing topological states is a key indicator for evaluating the variation in topological surface states after adsorption. This study provides a systematic understanding of the topological surface states of MgB₂ with different adsorbates, paving the way for future theoretical and experimental investigations in related fields and shedding light on the potential device applications of topological materials.

中文翻译：

氢、氢氧化物和水分子吸附引起的节线半金属MgB2拓扑表面态的变化

拓扑半金属由于其固有的拓扑物理特性和在器件中的潜在应用而引起了人们的极大兴趣。所有拓扑材料共有的一个关键特征是体边界对应，表明当体中存在非平凡的带拓扑时，边缘处存在独特的拓扑保护导电状态。先前对拓扑材料表面态的研究主要集中在原始表面，而对具有吸附物的拓扑半金属表面态的探索相对未知。这项工作基于从头计算，研究了 MgB ₂的拓扑表面态的变化，MgB 2 是一种众所周知的传统超导体和拓扑节点线半金属。我们采用以 Mg/B 原子作为表面终端的厚板模型来模拟其拓扑表面状态。随后，我们研究了氢（H）、氢氧化物（OH）和水（H ₂ O）在表面平板上的吸附，以观察表面状态的变化。原始板模型给出了表面投影节点线内的鼓面表面态，而吸附H、OH和H ₂ O后拓扑表面态发生了不同的变化，可以结合表面吸附吉布斯自由能Δ来系统地理解G 、表面终止和表面电荷密度分布。特别是，我们的研究结果表明，提供拓扑状态的表面原子的Bader电荷转移值是评估吸附后拓扑表面状态变化的关键指标。本研究系统地了解了具有不同吸附物的MgB ₂的拓扑表面态，为未来相关领域的理论和实验研究铺平了道路，并揭示了拓扑材料的潜在器件应用。

更新日期：2024-09-09

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南