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TT: Fachverband Tiefe Temperaturen
TT 68: Superconductivity: Properties and Electronic Structure
TT 68.1: Talk
Thursday, March 21, 2024, 09:30–09:45, H 3010
Possible unconventional vortex lattice in LiFeAs single crystals by µSR — •G. Lamura1, T. Shiroka2,3, T. Winyard4, M. Speight5, J. Quintanilla6, P. Gentile7, F. Anger8, and S. Wurmehl8 — 1Cnr-Spin, Genova, IT — 2ETH, Zurich, CH — 3Paul Scherrer Institut, CH — 4University of Edinburgh, UK — 5University of Leeds, UK — 6University of Kent, Canterbury, UK — 7Cnr-Spin, Salerno, IT — 8IFW, Dresden, DE
Muon spectroscopy (µSR) is able to study the vortex lattice (VL) of type II superconductors: positive muons implanted in interstitial sites probe different magnetic local fields Bloc depending on the relative position of Abrikosov vortices: the Fourier Transform of the measured time-dependent asymmetry FT { A(t) } ∝ n(Bloc), the local field distribution. A skyrmion-vortex chains model was recently proposed to distinguish nematic superconductors [1]. It consists of stripes of skyrmions (spatially separated half-quantum vortices) parameterized by the separation between the chains and the inter-skyrmion separation along the same chain: the resulting n(Bloc) presents a double-peak instead of the one-peak structure of the usual Abrikosov VL. Here we show our experimental results by µSR on a high-purity LiFeAs single crystal (Tc=17K) [2]. We likely found the evidence of such an unconventional mixed state: FT { A(t) } data at 2 K shows a small splitting of the main superconducting peak up to 7 K. This could confirm the nematicity of superconductivity in LiFeAs, in agreement with previous ARPES results [3].
[1] Phys. Rev. Lett. 130 (2023) 226002.
[2] J. Cryst. Growth 627 (2024) 127473.
[3] Phys. Rev. B 102 (2020) 184502.
Keywords: Nematic Superconductivity; Iron Based Superconductivity; Skyrmions; Stripes; Abrikosov Vortices