Fermion-statistics driven spin chirality and Young's Interference patterns in spin chirality of topological superconductors
by
MrArchisman Panigrahi(MIT)
→
Asia/Kolkata
A (304)
A
304
Description
In normal and superconducting metals with broken time-reversal symmetry (TRS), orbital currents in the ground state can induce spin-chirality through a mechanism driven solely by Fermion statistics. This effect does not rely on spin-dependent interactions, and can emerge even when the ground state remains spin-unpolarized. This chirality in the carrier band generates a chiral three-spin RKKY interaction between localized spins coupled to the carriers via the s-d Hamiltonian, an effect detectable by local probes like spin-sensitive STM.
In topological superconductors, the spatial distribution of chirality exhibits Young’s interference patterns near localized magnetic adatoms. The interference arises because Bogoliubov quasiparticles—coherent superpositions of electrons and holes—enable particle-to-hole conversion within the superconductor bulk. Magnetic adatoms act as beam splitters, enabling interference between particle and hole states, leading to spatial patterns similar to those observed in Young's double-slit experiment. We argue that such interference patterns also show up in other local observables.
These interference patterns are further modulated by nodal lines that encode the winding numbers of the superconducting gap function’s phase. In systems such as topological superconductors where detecting TRS breaking by conventional means is challenging, local detection of spin chirality provides a reliable diagnostic of superconducting topological phases and also provides insight about the nature of pairing.