Disorder-induced currents as signatures of chiral superconductivity
arXiv:2103.01244 · doi:10.1103/PhysRevB.104.094505
Abstract
Chiral superconductors are expected to carry a spontaneous, chiral and perpetual current along the sample edge. However, despite the availability of several candidate materials, such a current has not been observed in experiments. In this article, we suggest an alternative probe in the form of impurity-induced chiral currents. We first demonstrate that a single non-magnetic impurity induces an encircling chiral current. Its direction depends on the chirality of the order parameter and the sign of the impurity potential. Building on this observation, we consider the case of multiple impurities, e.g., realized as adatoms deposited on the surface of a candidate chiral superconductor. We contrast the response that is obtained in two cases: (a) when the impurities are all identical in sign and (b) when the impurities have mixed positive and negative signs. The former leads to coherent currents within the sample, arising from the fusion of individual current loops. The latter produces loops of random chirality that lead to incoherent local currents. These two scenarios can be distinguished by measuring the induced magnetic field using recent probes such as diamond NV centres. We argue that impurity-induced currents may be easier to observe than edge currents, as they can be tuned by varying impurity strength and concentration. We demonstrate these results using a toy model for superconductivity on a square lattice. We develop an improved scheme for Bogoliubov deGennes (BdG) simulations where both the order parameter as well as the magnetic field are determined self-consistently.
arXiv comment8 pages, 6 figures
References in corpus (26)
- Chiral superconductivity from repulsive interactions in doped graphene
- Probing condensed matter physics with magnetometry based on nitrogen-vacancy centres in diamond
- Evaluation of Spin-Triplet Superconductivity in Sr2RuO4
- Microscopic evidence for a chiral superconducting order parameter in the heavy fermion superconductor UTe2
- Evidence for superconductivity in Li-decorated monolayer graphene
- Chiral Superconductors
- Imaging viscous flow of the Dirac fluid in graphene
- Quasiparticle States near the Surface and the Domain Wall in a p_x\pm i p_y-Wave Superconductor
- Quantum imaging of current flow in graphene
- Imaging currents in HgTe quantum wells in the quantum spin Hall regime
- Topological superconductivity in monolayer transition metal dichalcogenides
- Upper limit on spontaneous supercurrents in SrRuO
- Chiral d-wave superconductivity in doped graphene
- Evidence for Time-Reversal-Symmetry-Broken Superconductivity in Locally Noncentrosymmetric SrPtAs
- Limits on Superconductivity-Related Magnetization in SrRuO and PrOsSb from Scanning SQUID Microscopy
- Spontaneous Hall effect in chiral p-wave superconductor
- Observation of an edge supercurrent in the Weyl superconductor MoTe
- Imaging work and dissipation in the quantum Hall state in graphene
- Suppression of spontaneous currents in SrRuO by surface disorder
- Electronic correlations stabilizing time-reversal broken chiral superconductivity in single-trilayer TiSe
- Properties of edge states in spin-triplet two-band superconductor
- Suppression of Spontaneous Supercurrents in a Chiral p-Wave Superconductor
- Topological state engineering by potential impurities on chiral superconductors
- Impurity- and Magnetic-field-induced Quasiparticle States in Chiral -wave Superconductors
- Tunable topological states hosted by unconventional superconductors with adatoms
- Impurity induced current in a Chern insulator