Probing the superconducting gap structure in the noncentrosymmetric topological superconductor ZrRuAs

Abstract

The superconducting gap structure of the topological superconductor candidate ZrRuAs with a noncentrosymmetric crystal structure has been investigated using muon-spin rotation/relaxation (μSR) measurements in transverse-field (TF) and zero-field (ZF) geometries. Magnetization, electrical resistivity, and heat capacity measurements reveal bulk superconductivity below a superconducting transition temperature T c = 7.9(1) K. The temperature dependence of the effective penetration depth obtained from the TF-μSR spectra, and the electronic heat capacity in the superconducting state, are well described by an isotropic s-wave gap model. Comparison of the electronic mean free path with the superconducting coherence length suggests superconductivity in the dirty limit. ZF μSR data show there is no significant change in the muon-spin relaxation rate above and below T c , indicating that time-reversal symmetry is preserved in the superconducting state.

Unconventional Pressure Dependence of the Superfluid Density in the Nodeless Topological Superconductor α−PdBi2

“…Thus, TSC has attracted significant research interest recently due to its scientific importance and potential application prospects. Despite serious research efforts, the experimental realizations of bulk topological superconductivity in real materials remain considerably limited to a few classes of materials such as Cu=Sr=Nb-doped Bi 2 Se 3 [8][9][10][11][12][13], layered transition metal dichalcogenides [14][15][16][17], ternary transition metal pnictides [18,19], In-doped SnTe [20], and a few half-Heusler compounds [21,22]. Interestingly, recent reports investigating various members of the Pd-Bi family have reinvigorated the interest in searching for potential TSCs in this class of materials.…”

NbReSi: A Noncentrosymetric Superconductor with Large Upper Critical Field

“…In addition, the observation of TRS breaking in some Re-based superconductors suggests an important role played by Re. While the previous µSR studies on the Refree ZrNiAl-type ZrRuAs and LaPdIn suggest a preserved TRS in their superconducting states [41,42]. Therefore, it is of particular interest to determine whether the TRS is broken in the superconducting state of NbReSi, which might further shed light on the origin of TRS breaking in the Re-based superconductor.…”

“…The ZrNiAl-type compounds are another important family of noncentrosymmetric superconductors. (Zr,Hf)RuP [38] and ZrRu(As,Si) [39,40], which were synthesized under high pressure, exhibit relatively high superconducting transition temperatures T c ∼ 10 K. Both ZrRuAs [41] and LaPdIn [42] are fully-gapped superconductors with preserved TRS. NbReSi also crys-tallizes in a ZrNiAl-type structure [43], but its physical properties are not yet well studied.…”

Superconducting ground state of the nonsymmorphic superconducting compound Zr2Ir

“…Recently, experimental studies performed on theoretically predicted topological binary and ternary superconducting compounds such as NbC, TaC [13], and A15 Ti 3 X (X = Ir, Sb) [14,15], ZrRuAs [16], and kagome flat-band LaRu 3 Si 2 [17] have shown conventional s-wave superconductivity with preserved time-reversal symmetry (TRS). In contrast, multigap superconductivity has been reported in the topological superconducting candidate TaOsSi [18] and TRS is preserved.…”