Optical and Raman selection rules for odd-parity clean superconductors

Fuente: arXiv
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Main Authors: Lu, Shuangyuan, Yang, Xu, Lu, Yuan-Ming
Format: Preprint
Published: 2024
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author Lu, Shuangyuan
Yang, Xu
Lu, Yuan-Ming
author_facet Lu, Shuangyuan
Yang, Xu
Lu, Yuan-Ming
contents We derive selection rules in optical absorption and Raman scattering spectra, that can determine the parity of pairing order parameters under inversion symmetry in two classes of \emph{clean} superconductors: (i) chiral superconductors with strong spin-orbit couplings, (ii) singlet superconductors with negligible spin-orbit couplings. Experimentally, the inversion parity of pair wave functions can be determined by comparing the "optical gap" $Δ_\text{op}$ in Raman and optical spectroscopy and the "thermodynamic gap" $2Δ$ in specific heat measurements, and the selection rules apply when $Δ_\text{op}>2Δ$. We demonstrate the selection rules in superconductivity in models of (i) doped Weyl semimetals and (ii) doped graphene. Our derivation is based on the relation between pairing symmetry and fermion projective symmetry group of a superconductor. We further derive similar selection rules for two-dimensional superconductors with 2-fold rotational symmetry, and discuss how they apply to the superconducting state in magic-angle twisted bilayer graphene.
format Preprint
id arxiv_https___arxiv_org_abs_2406_14523
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Optical and Raman selection rules for odd-parity clean superconductors
Lu, Shuangyuan
Yang, Xu
Lu, Yuan-Ming
Strongly Correlated Electrons
Superconductivity
We derive selection rules in optical absorption and Raman scattering spectra, that can determine the parity of pairing order parameters under inversion symmetry in two classes of \emph{clean} superconductors: (i) chiral superconductors with strong spin-orbit couplings, (ii) singlet superconductors with negligible spin-orbit couplings. Experimentally, the inversion parity of pair wave functions can be determined by comparing the "optical gap" $Δ_\text{op}$ in Raman and optical spectroscopy and the "thermodynamic gap" $2Δ$ in specific heat measurements, and the selection rules apply when $Δ_\text{op}>2Δ$. We demonstrate the selection rules in superconductivity in models of (i) doped Weyl semimetals and (ii) doped graphene. Our derivation is based on the relation between pairing symmetry and fermion projective symmetry group of a superconductor. We further derive similar selection rules for two-dimensional superconductors with 2-fold rotational symmetry, and discuss how they apply to the superconducting state in magic-angle twisted bilayer graphene.
title Optical and Raman selection rules for odd-parity clean superconductors
topic Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2406.14523