Quest for nematicity in iron-based superconductors

探索铁基超导体的向列性

• 批准号: 399159082
• 负责人: Dr. Liran Wang
• 金额: --
• 依托单位: Institut für QuantenMaterialien und Technologien (IQMT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/399159082?language=en
• 关键词: Quest; nematicity; iron; based; superconductors

One of the fundamental new discoveries on superconductors in the recent years is the experimental observation of electronic nematicity, i.e., a spontaneous symmetry breaking, which is crucial for understanding superconductivity in pnictide superconductors as well as for many other materials. It is associated with the evolution of short-range electronic order, however, the mechanisms of its formation as well as its interdependencies with superconductivity are not yet clear. The current proposal asks for extension of the ongoing project on the quest for nematicity in in iron-based superconductors which yielded a variety of important results and has raised further relevant questions. The main and unique experimental technique will still be the dilatometric bending method to investigate electronic nematic order in iron based superconductors. The very successful collaboration between Heidelberg University and KIT which includes sharing of labs for the project will be extended. During the past project year, our main focus was on 1111 and 122 systems where successful studies on nematicity have been done and published. Notably, our analysis of 1111 and 122 data in the first project phase has shown that a more thorough comparison of elastoresistivity and 3-point bending data is needed as compared to the previous literature. In the remaining time of the first project phase, we will finish studies on LiFeAs and NaFeAs as outlined in the work plan. The third year which funding is applied for in the proposal at hand will particularly focus on 11 and further 122 systems, i.e., on Eu(Fe1−xCox)2As2 and FeSe1-xTex with various doping levels as well as some rare-earth 1111 samples. All these materials have not yet studied by means of the bending method. In case of the new Eu(Fe1−xCox)2As2 and FeSe1-xTex single crystals, the bending data will be corroborated by thermal expansion studies which also do not exist in the literature. The dilatometric studies in the project will be accompanied by relevant experimental and theory studies by our collaborators, including, e.g., anisotropic resistivity, specific heat, and numeric analysis for nematic order-parameter using DFT calculation.

电子向列性的实验观测是近年来超导体研究的一个重要新发现，自发对称破缺，这对于理解磷属元素化物超导体以及许多其他材料的超导性至关重要。它与短程电子有序的演化有关，然而，它的形成机制以及它与超导电性的相互依赖关系尚不清楚。目前的提案要求延长正在进行的关于在铁基超导体中探索向列性的项目，该项目产生了各种重要结果，并提出了进一步的相关问题。铁基超导体电子有序性研究的主要和独特的实验技术仍将是弯曲测量法。海德堡大学和KIT之间非常成功的合作，包括为该项目共享实验室，将得到扩展。在过去的项目年中，我们的主要重点是1111和122系统，成功的向列性研究已经完成并发表。值得注意的是，我们对第一个项目阶段的1111和122数据的分析表明，与以前的文献相比，需要对弹性电阻率和三点弯曲数据进行更彻底的比较。在项目第一阶段的剩余时间内，我们将完成工作计划中概述的LiFeAs和NaFeAs研究。目前提案中申请资金的第三年将特别侧重于11个和另外122个系统，即，在Eu（Fe1-xCox）2As2和FeSe1-xTex上进行了各种掺杂水平的测试，以及一些稀土1111样品。所有这些材料还没有研究过弯曲方法。在新的Eu（Fe1-xCox）2As2和FeSe1-xTex单晶的情况下，弯曲数据将通过文献中也不存在的热膨胀研究来证实。该项目中的生物计量学研究将伴随着我们合作者的相关实验和理论研究，包括，例如，各向异性电阻率、比热以及利用DFT计算对介电常数进行数值分析。

项目成果

Electronic Nematicity in URu2Si2 Revisited

重新审视 URu2Si2 中的电子向列性

• DOI: 10.1103/physrevlett.124.257601
• 发表时间: 2020
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Liran Wang;Mingquan He;Frédéric Hardy;Dai Aoki;Kristin Willa;Jacques Flouquet;Christoph Meingast
• 通讯作者: Christoph Meingast

The Complex Electronic Phase Diagram of Single-Crystalline R2PdSi3 (R = Ho, Dy) Studied by Thermal Expansion and Magnetostriction

热膨胀和磁致伸缩研究单晶R2PdSi3(R=Ho,Dy)的复杂电子相图

• DOI: 10.7566/jpsj.88.094709
• 发表时间: 2019
• 期刊: Journal of the Physical Society of Japan
• 影响因子: 1.7

Calorimetric evidence of nodal gaps in the nematic superconductor FeSe

• DOI: 10.1103/physrevb.99.035157
• 发表时间: 2018-07
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: F. Hardy;M. He;Liran Wang;Thomas Wolf;P. Schweiss;M. Merz;Maik Barth;P. Adelmann;R. Eder;A. Haghighirad;C. Meingast

Competing Electronic Phases near the Onset of Superconductivity in Hole-doped SrFe2As2

空穴掺杂 SrFe2As2 超导开始时的竞争电子相

• DOI: 10.7566/jpsj.88.104710
• 发表时间: 2019
• 期刊: Journal of the Physical Society of Japan
• 影响因子: 1.7