Strain-induced Berry phase in chiral superconductors

2025/11/24 by Sun, Canon, Franz, Marcel, Maciejko, Joseph
#FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)

paper · doi:10.48550/arxiv.2511.18753

Abstract

We study the topology of the order parameter in the intermediate phase between the superconducting and time-reversal symmetry breaking transitions of a p_x+ip_y superconductor under strain. The application of in-plane strain reduces the underlying crystal symmetry and lifts the degeneracy of the critical temperature between the p_x and p_y orbitals, resulting in a Dirac cone structure in the thermodynamic phase diagram. When the strain is varied adiabatically along a closed path enclosing the Dirac cone, the order parameter acquires a Berry phase of π, which originates from a half rotation of the superconducting gap function. This half rotation leaves a topological signature in the superfluid stiffness tensor, making it directly observable through the geometry of vortices and the upper critical field.

Citations

• Topological Landau Theory
• Measuring kinetic inductance and superfluid stiffness of two-dimensional superconductors using high-quality transmission-line resonators
• Constraints on a split superconducting transition under uniaxial strain in Sr₂RuO₄ from scanning SQUID microscopy

Related

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• Strain Modulation Effects on the Topological Properties of a Chiral p-Wave Superconductor
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• Family of multilayer graphene superconductors with tunable chirality: Momentum-space vortices nucleated by a ring of Berry curvature
• Signature of chiral superconducting order parameter evidenced in mesoscopic superconductors