Probing the superconducting gap structure of (Li1−xFex)OHFeSe

Abstract

We report measurements of the London penetration depth [∆λ(T )] of the recently discovered ironbased superconductor (Li1−xFex)OHFeSe, in order to characterize the nature of the superconducting gap structure. At low temperatures, ∆λ(T ) displays nearly temperature independent behavior, indicating a fully open superconducting gap. We also analyze the superfluid density ρs(T ) which cannot be well accounted for by a single-gap isotropic s-wave model but are consistent with either two-gaps, a model for the orbital selective s × τ3 state or anisotropic s-wave superconductivity.

Probing pairing symmetry in multi-band superconductors by quasiparticle interference

“…In the light of recent theoretical results obtained 39–43 with only electron pockets, we study and present the variation in response function behaviour, when sgn( β ) is +1, with the 2D plot given in Fig. 5.…”

Temperature dependent local inhomogeneity and magnetic moments of (Li1−xFex)OHFeSe superconductors

“…35,36 In addition to its high T c superconductivity, (Li 1− x Fe x )OHFeSe has attracted significant attention for its electronic and magnetic properties. 20,34,36–38 In particular, similar to K x Fe 2− x Se 2 , (Li 1− x Fe x )OHFeSe shows the absence of hole bands on the Fermi surface 15,39 and that superconductivity appears to coexist with antiferromagnetism in the phase diagram with a spin density wave (SDW) state occurring below T N ∼ 125 K. 40–42 On the other hand, unlike K x Fe 2− x Se 2 , no Fe vacancy or phase separation has been reported by diffraction experiments, making it a promising candidate to study the physical effects of intercalation in iron–chalcogenide superconductors. Recent studies 40–42 confirm a peculiar relationship between structural parameters ( i.e.…”

Síntese de amostras policristalinas de HfV>sub<2>/sub<Ga>sub<4>/sub< e caracterização experimental de suas propriedades supercondutoras não convencionais

“…−1 e ∆(T, φ ) descreve a o gap supercondutor como função da temperatura e do ângulo azimutal ao longo da superfície de Fermi segundo a equação: ∆(T, φ ) = ∆ 0 δ (T/T c )g(φ ), com ∆ 0 sendo o maior valor possível para gap supercondutor em T = 0 K. Nessa equação, a dependência do gap com a temperatura é dada por δ (T/T c ) = tanh{1,82[1.018(T c /T -1)] 0,51 }, já a dependência angular g(φ ) possui valor igual a 1 caso o gap seja descrito por uma função de onda do tipo s ou igual a cos(2φ ) caso a função de onda seja do tipo d (PANG et al, 2015;ANNETT, 1989). Além das equações apresentadas, a utilização de outros modelos permite descrever a simetria do gap supercondutor para além de uma função de onda do tipo s ou d (NICA; YU; SI, 2017;LIN et al, 2011;SMIDMAN et al, 2017).…”