Uniaxial strain control of spin-polarization in multicomponent nematic order of BaFe\(_{2}\)As\(_{2}\)

• Published in: arXiv.org
• Main Authors: Kissikov, T, Sarkar, R, Lawson, M, Bush, B T, Timmons, E I, Tanatar, M A, Prozorov, R, Bud'ko, S L, Canfield, P C, Fernandes, R M, Curro, N J
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 11.04.2017
• Subjects: Anisotropy; Complexity; Degrees of freedom; High temperature superconductors; Liquid crystals; Magnetic variations; Nematic crystals; NMR; Nuclear magnetic resonance; Order parameters; Orthorhombic lattice; Phase diagrams; Physics - Strongly Correlated Electrons; Polarization (spin alignment); Spin structure; Spin-orbit interactions
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1704.03566

The iron-based high temperature superconductors exhibit a rich phase diagram reflecting a complex interplay between spin, lattice, and orbital degrees of freedom [1-4]. The nematic state observed in many of these compounds epitomizes this complexity, by entangling a real-space anisotropy in the spin fluctuation spectrum with ferro-orbital order and an orthorhombic lattice distortion [5-7]. A more subtle and much less explored facet of the interplay between these degrees of freedom arises from the sizable spin-orbit coupling present in these systems, which translates anisotropies in real space into anisotropies in spin space. Here, we present a new technique enabling nuclear magnetic resonance under precise tunable strain control, which reveals that upon application of a tetragonal symmetry-breaking strain field, the magnetic fluctuation spectrum in the paramagnetic phase of BaFe\(_{2}\)As\(_{2}\) also acquires an anisotropic response in spin-space. Our results unveil a hitherto uncharted internal spin structure of the nematic order parameter, indicating that similar to liquid crystals, electronic nematic materials may offer a novel route to magneto-mechanical control.