TY - JOUR
T1 - Unconventional superconductivity near a nematic instability in a multi-orbital system
AU - Islam, Kazi Ranjibul
AU - Chubukov, Andrey
N1 - Publisher Copyright:
© The Author(s) 2024.
PY - 2024/12
Y1 - 2024/12
N2 - We analyze superconductivity in a multi-orbital fermionic system near the onset of a nematic order, using doped FeSe as an example. We associate nematicity with spontaneous polarization between dxz and dyz orbitals. We derive pairing interaction, mediated by soft nematic fluctuations, and show that it is attractive, and its strength depends on the position on the Fermi surface. As the consequence, right at the nematic quantum-critical point (QCP), superconducting gap opens up at Tc only at special points and extends into finite arcs at T < Tc. In between the arcs the Fermi surface remains intact. This leads to highly unconventional behavior of the specific heat, with no jump at Tc and seemingly finite offset at T = 0. We discuss gap structure and pairing symmetry away from a QCP and compare nematic and spin-fluctuation scenarios. We apply the results to FeSe1−xSx and FeSe1−xTex.
AB - We analyze superconductivity in a multi-orbital fermionic system near the onset of a nematic order, using doped FeSe as an example. We associate nematicity with spontaneous polarization between dxz and dyz orbitals. We derive pairing interaction, mediated by soft nematic fluctuations, and show that it is attractive, and its strength depends on the position on the Fermi surface. As the consequence, right at the nematic quantum-critical point (QCP), superconducting gap opens up at Tc only at special points and extends into finite arcs at T < Tc. In between the arcs the Fermi surface remains intact. This leads to highly unconventional behavior of the specific heat, with no jump at Tc and seemingly finite offset at T = 0. We discuss gap structure and pairing symmetry away from a QCP and compare nematic and spin-fluctuation scenarios. We apply the results to FeSe1−xSx and FeSe1−xTex.
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U2 - 10.1038/s41535-024-00638-2
DO - 10.1038/s41535-024-00638-2
M3 - Article
AN - SCOPUS:85188125838
SN - 2397-4648
VL - 9
JO - npj Quantum Materials
JF - npj Quantum Materials
IS - 1
M1 - 28
ER -