Nematic susceptibility and quantum oscillations in uniaxially stressed FeSe and LaFePO.

本研究旨在通过X射线结构研究和量子振荡测量，研究化学计量比铁基化合物FeSe和LaFePO在单轴强应力下的结构。我们的目标是双重的。1.泊松比-dεyy/dεxx，其中εxx和εyy分别是纵向应变和横向应变，可以作为向列相敏感性的量度吗？目前，弹性电阻率d(ρxx-ρyy)/d(εxx-εyy)是测量向列相磁化率的常规探头，但由于电阻率不是热力学变量，其分析实用性受到限制。2.这些化合物的电子结构是如何在强烈的单轴扭曲下演化的，从而诱导或增强向列相有序？这一知识将帮助我们更好地解开非应力化合物中的电子相互作用。我们建议招聘一名学生，他或她的时间将大致平均分配给德累斯顿州立大学和MPI-CPfS。

This proposal is to study the stoichiometric iron-based compounds FeSe and LaFePO under strong uniaxial stress, through X-ray structural studies and measurements of quantum oscillations. The goal is two-fold. 1. Can the Poisson’s ratio -dεyy/dεxx, where εxx and εyy are respectively the longitudinal and transverse strains, serve as a measure of nematic susceptibility? At present the elastoresistivity d(ρxx - ρyy)/d(εxx - εyy) is the conventional probe of nematic susceptibility but its analytical usefulness is limited by the fact that resistivity is not a thermodynamic quantity. 2. How do the electronic structures of these compounds evolve under strong uniaxial distortion, that induces or enhances nematic order? This knowledge will help us better untangle the electronic interactions in the unstressed compounds. We propose to hire one student, who will split his or her time approximately equally between TU Dresden and MPI-CPfS.