Dirac materials in square lattice compounds

方格化合物中的狄拉克材料

• 批准号: 335449904
• 负责人: Dr. Christian Reinhard Ast, since 9/2017
• 金额: --
• 依托单位: Max-Planck-Institut für Festkörperforschung (MPI-FKF)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/335449904?language=en
• 关键词: Dirac; materials; square; lattice; compounds

Materials that exhibit the same electronic structure as graphene but are three dimensional (so called 3D Dirac Semimetals) have received a lot of attention recently from both fundamental and applied sciences. For once they exhibit exceptional physical properties such as very high magnetoresistance or carrier mobility, but they can also lead to the discovery of new particles that were predicted in high energy physics, but can be observed in the solid state if the materials has the correct band structure. Currently the amount of such 3D Dirac semimetals is limited and many of them show either drawbacks in their fundamental properties, i.e. their electronic structure or also in their potential to be used in future devices due to their toxicity, cost or instability in ambient conditions. The aim of this proposal is to find more 3D Dirac materials that do not bear these disadvantages. Recently we introduced a new material, ZrSiS, that is not only a cheap stable and non toxic alternative to current 3D Dirac materials, but also has an electronic structure that is of interest for fundamental physics. On the one hand the Dirac bands are linearly dispersed over a very large range of energy which allows for more defects in the crystals while still having the Fermi level located within the region of linearly dispersed bands. On the other hand ZrSiS features a Dirac cone that is protected by non-symmorphic symmetry, a transnational symmetry element that has gained significant interest by theorists for the prediction of new Dirac materials and also new fermions. We showed for the first time that it is possible to observe this predicted feature in the electronic structure experimentally. Now, we would like to expand the number of materials with related electronic structures. ZrSiS is a good starting point to look for more materials with this interesting physical properties. For once, it crystallizes in a common crystal structure (PbFCl structure type), but also, the important feature for the electronic structure can be traced back to the square net arrangement of atoms, a feature that can also arise in many more structure types, allowing for a very large number of compounds to explore. We will identify materials of interest with ab initio calculations, synthesize them, and investigate them with angle resolved photoemission spectroscopy (ARPES) and transport studies.

具有与石墨烯相同电子结构的三维材料（即所谓的三维狄拉克半金属）最近受到了基础科学和应用科学的广泛关注。一旦它们表现出特殊的物理特性，如非常高的磁电阻或载流子迁移率，但它们也可以导致发现在高能物理学中预测的新粒子，但如果材料具有正确的能带结构，则可以在固态中观察到这些粒子。目前，这种3D Dirac半金属的数量是有限的，其中许多在其基本性质（即电子结构）或由于其毒性、成本或在环境条件下的不稳定性而在未来设备中使用的潜力方面存在缺陷。这项提议的目的是寻找更多的3D狄拉克材料，不承担这些缺点。最近，我们推出了一种新材料，zrsi，它不仅是一种廉价、稳定、无毒的3D狄拉克材料替代品，而且具有基础物理学感兴趣的电子结构。一方面，狄拉克带在很大的能量范围内线性分散，这使得晶体中存在更多的缺陷，同时费米能级仍然位于线性分散带的区域内。另一方面，zrsi具有受非对称对称保护的狄拉克锥，这是一种跨国对称元素，在预测新的狄拉克材料和新的费米子方面引起了理论家的极大兴趣。我们首次在实验中证明了在电子结构中观察到这种预测特征是可能的。现在，我们想扩大具有相关电子结构的材料的数量。zrsi是寻找更多具有这种有趣物理性质的材料的一个很好的起点。这一次，它以一种常见的晶体结构（pbcl结构类型）结晶，而且，电子结构的重要特征可以追溯到原子的方网排列，这一特征也可以出现在许多更多的结构类型中，允许探索大量的化合物。我们将通过从头计算确定感兴趣的材料，合成它们，并用角度分辨光发射光谱（ARPES）和输运研究来研究它们。