Fermi surface and topology of multiband superconductor BeAu

Abstract

The chiral material BeAu was recently identified as a multiband type-I superconductor with a critical temperature of 3.2 K. As a member of the B20 crystal family (space group $P{2}_{1}3$), its band structure hosts multifold fermions at high-symmetry points, unpaired Weyl points and even nodal surfaces. This renders BeAu an appealing system to investigate the interplay between superconductivity and topology. Here we present a comprehensive first-principles analysis of BeAu's electronic structure focusing on its Fermi surface's topology and the implications for superconductivity. Together with the presence of four- and six-fold fermions at high-symmetry points, we identify several additional isolated Weyl points near the Fermi level. We also determine the associated topological edge states -- the surface Fermi arcs. Computing the Chern number associated to different Fermi surface sheets, we show that BeAu harbors a $\nu =4$ topological superconducting phase in the presence of $s$-wave pairing of alternating sign ($s_{\pm }$ pairing). Notably, we also identify a Fermi surface with a Chern number of +6; the highest value reported to date. Finally, our analysis reveals strong inhomogeneity in the orbital character of electronic states at the Fermi level, suggesting a link to the observed multigap superconductivity.

arXiv comment8 pages, 5 figures

References in corpus (28)

• Beyond Dirac and Weyl fermions: Unconventional quasiparticles in conventional crystals
• Berry Curvature on the Fermi Surface: Anomalous Hall Effect as a Topological Fermi-Liquid Property
• Quantized circular photogalvanic effect in Weyl semimetals
• Large Fermi Arcs in Unconventional Weyl Semimetal RhSi
• Nodal surface semimetals: Theory and material realization
• Fermi Surface Topological Invariants for Time Reversal Invariant Superconductors
• Chiral Optical Response of Multifold Fermions
• Time-reversal invariant topological superconductivity in doped Weyl semimetals
• Linear and nonlinear optical responses in the chiral multifold semimetal RhSi
• Observation of giant spin-split Fermi-arc with maximal Chern number in the chiral topological semimetal PtGa
• Circumventing the no-go theorem: A single Weyl point surrounded by nodal walls
• Superconducting Arcs
• Parallel spin-momentum locking in a chiral topological semimetal
• Observation of a singular Weyl point surrounded by charged nodal walls in PtGa
• Type-I superconductivity in noncentrosymmetric superconductor AuBe
• muSR and Magnetometry Study of the Type-I Superconductor BeAu
• Multiple-gap response of type-I noncentrosymmetric BeAu superconductor
• The single- vs. two-gap scenario: the specific heat and the thermodynamic critical field of BeAu superconductor
• Intrinsic surface superconducting instability in Type-I Weyl Semimetals
• Gate-dependent non-linear Hall effect at room temperature in topological semimetal GeTe
• Cubic Hall viscosity in three-dimensional topological semimetals
• Topological Circular Dichroism in Chiral Multifold Semimetals
• Fundamental laws of chiral band crossings: local constraints, global constraints, and topological phase diagrams
• Self-consistent surface superconductivity in time-reversal symmetric Weyl semimetals
• Topological multiband s-wave superconductivity in coupled multifold fermions
• Spectroscopic evidence of multi-gap superconductivity in non-centrosymmetric AuBe
• Influence of pressure on properties of multi-gap type-I superconductor BeAu
• Three-dimensional time reversal invariant topological superconductivity in doped chiral topological semimetals