Ferromagnetism and Superconductivity in LiFeAs

LiFeAs 中的铁磁性和超导性

• 批准号: 237770753
• 负责人: Professor Dr. Bernd Büchner
• 金额: --
• 依托单位: Institut für Festkörperforschung
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/237770753?language=en
• 关键词: Ferromagnetism; Superconductivity; LiFeAs

LiFeAs is radically different from the canonical iron-arsenide superconductors, where strong nesting between hole-like and electron-like Fermi surface (FS) pockets causes an antiferromagnetic spin density wave (SDW) ground state in the undoped parent compounds. Superconductivity emerges already without doping, at a relatively high critical temperature of about 18K. The FS of LiFeAs is poorly nested and the topf of two hole-like bands at the Gammapoint almost touch the Fermi level yielding a structure close to a van-Hove singularity. Our prelminiary data show ferromagnetism in Li deficient LiFeAs, i.e. LiFeAs is a pnictide superconductor close to a ferromagnetic phase. The determination and interpretation of the electronic phase diagram including the change from ferromagnetism to superconductivity and the investigation of consequences of the proximity of these two competing states are the central objectives of this project. These challenging task will be tackled by a combination of experimental and theoretical efforts.

LiFeAs与典型的铁砷化超导体完全不同，在铁砷化超导体中，类空穴和类电子费米表面（FS）口袋之间的强嵌套在未掺杂的母体化合物中引起反铁磁自旋密度波（SDW）基态。在没有掺杂的情况下，超导性已经出现，临界温度相对较高，约为18 K。的FS的LiFeAs是不良的嵌套和两个孔状带在伽玛点的topf几乎触及费米能级产生的结构接近于一个van-Hove奇点。我们的初步数据表明缺Li的LiFeAs具有铁磁性，即LiFeAs是一种接近铁磁相的磷属元素化物超导体。该项目的中心目标是确定和解释电子相图，包括从铁磁性到超导性的变化，以及调查这两种竞争状态接近的后果。这些具有挑战性的任务将通过实验和理论的努力相结合来解决。