Controlling superconductivity via electron doping in YFe<sub>2</sub>Ge<sub>2</sub>

ORAL

Abstract

Iron-based superconductors are a valuable platform to study the interplay of magnetism and unconventional superconductivity. YFe2Ge2 stands out because it does not contain pnictogen or chalcogen elements and its Fermi surface is more three-dimensional [1]. Bulk superconductivity in YFe2Ge2 was discovered with a transition temperature of about 1.8 K in single crystals [2], yet heat capacity measurements indicate that the superconducting gap has a sign-changing nature [3], and the exact symmetry remains an open question. The compound can be represented as Y3+(Fe2.5+)2(Ge4-)2 , showing that the Fe atoms are hole doped relative to the typical Fe2+ configuration. We use density functional theory calculations and the random phase approximation to calculate the pairing potential. The gap symmetry and pairing strength are studied as a function of electron doping.

[1] Y. Zou et al., Phys. Status Solidi RRL 8, 11, 928–930 (2014).

[2] D. J. Singh, Phys. Rev. B 89, 024505 (2014).

[3] J. Chen et al., Phys. Rev. Lett. 125, 237002 (2020).

*Theory work was supported the U.S. Dept. of Energy (DOE), Office of Science (SC) under grant award number DE-SC0025748, DOE RENEW. Computational resources of the Compute and Data Environment for Science (CADES) under Contract No. DE-AC05-00OR22725 were used as part of a user project at the Center for Nanophase Materials Sciences (CNMS), which is a U.S. DOE, SC User Facility at Oak Ridge National Laboratory.

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Presenters

  • John W Villanova

    • Middle Tennessee State University

Authors

  • John W Villanova

    • Middle Tennessee State University

  • Tom Berlijn

    • Oak Ridge National Laboratory

  • Cameron Morelli

    • Middle Tennessee State University

  • Thomas A Maier

    • Oak Ridge National Laboratory