Ubiquity of rotational symmetry breaking in superconducting films, from Fe(Te,Se)/Bi${}_2$Te${}_3$ to Nb, and the effect of measurement geometry

Abstract

FeTe${}_{0.5}$Se${}_{0.5}$/Bi${}_2$Te${}_3$ heterostructure is a promising new platform in the journey toward topological quantum computation, considering that first, FeTe${}_{0.5}$Se${}_{0.5}$ is itself known to be a topological superconductor (TSC) and second, the heterostructure has topological interface states that can be proximitized into TSC even if FTS fails to become TSC on its own. Here, we show that this system exhibits quasi-2D superconductivity, and utilizing the standard in-plane magneto-transport measurements, we discover two-fold anisotropy (a.k.a nematicity) in R${}_{xx}$ and I${}_c$ measurement, even though the system exhibits globally 12-fold symmetry. Then, we carried out similar measurements on a polycrystalline niobium (Nb) thin film, a well-known s-wave elemental superconductor, and found a similar two-fold symmetry even for this Nb system. This implies either that nematic behavior is ubiquitous or that the in-plane magneto-transport measurement scheme routinely used to detect nematicity is not a reliable method to probe nematicity. We show that the angle-dependent response of vortices in the superconducting regime to the magnetic Lorentz force is very likely the main cause behind the ubiquitous nematic behaviors of this measurement scheme. In other words, this measurement scheme is intrinsically two-fold, and is therefore not suitable to detect the nematicity. Accordingly, all the previous reports of nematicity based on similar measurement practices, reported on various samples, including thin films, bulk crystals, and exfoliated flakes, need to be reinterpreted.

References in corpus (20)

• Superconductivity in single-layer films of FeSe with a transition temperature above 100 K
• Evidence for an electron nematic phase transition in underdoped iron pnictide superconductors
• Nematicity and Competing Orders in Superconducting Magic-Angle Graphene
• Ironing out the details of unconventional superconductivity
• Zero-energy vortex bound state in the superconducting topological surface state of Fe(Se,Te)
• Unexpected two-fold symmetric superconductivity in few-layer NbSe${}_2$
• Atomic line defects and zero-energy end states in monolayer Fe(Te,Se) high-temperature superconductors
• Intrinsic pinning and the critical current scaling of clean epitaxial Fe(Se,Te) thin films
• Thermopower as sensitive probe of electronic nematicity in iron pnictides
• Spectroscopic Evidence of Superconductivity Pairing at 83 K in Single-Layer FeSe/SrTiO3 Films
• Chiral to Nematic Crossover in the Superconducting State of 4Hb-TaS${}_2$
• Spin-excitation anisotropy in the nematic state of detwinned FeSe
• Competing pairing interactions responsible for the large upper critical field in a stoichiometric iron-based superconductor, CaKFe${}_4$As${}_4$
• Spontaneous rotational symmetry breaking in KTaO${}_3$ heterointerface superconductors
• Anisotropy of the in-plane angular magnetoresistance of electron-doed Sr1-xLaxCuO2 thin films
• Hybrid symmetry epitaxy of superconducting Fe(Te,Se) film on a topological insulator
• Phase-manipulation-induced Majorana Mode and Braiding Realization in Iron-based Superconductor Fe(Te,Se)
• Monolayer superconductivity and tunable topological electronic structure at the Fe(Te,Se)/Bi2Te3 interface
• Evidence for a robust sign-changing s-wave order parameter in monolayer films of superconducting Fe (Se,Te)/Bi2Te3
• Ubiquity of rotational symmetry breaking in superconducting films, from Fe(Te,Se)/Bi${}_2$Te${}_3$ to Nb, and the effect of measurement geometry

Cited by in corpus (1)

• Ubiquity of rotational symmetry breaking in superconducting films, from Fe(Te,Se)/Bi${}_2$Te${}_3$ to Nb, and the effect of measurement geometry