Singlet, triplet, and mixed all-to-all pairing states emerging from incoherent fermions
arxiv(2024)
摘要
The electron-electron and electron-phonon coupling in complex materials can
be more complicated than simple density-density interactions, involving
intertwined dynamics of spin, charge, and spatial symmetries. This motivates
studying universal models with complex interactions, and studying whether in
this case BCS-type singlet pairing is still the “natural” fate of the system.
To this end, we construct a Yukawa-SYK model with nonlocal couplings in both
spin and charge channels. Furthermore, we provide for time-reversal-symmetry
breaking dynamics by averaging over the Gaussian Unitary ensemble rather than
the Orthogonal ensemble. We find that the ground state of the system can be an
orbitally nonlocal superconducting state arising from incoherent fermions with
no BCS-like analog. The superconductivity has an equal tendency to triplet and
singlet pairing states separated by a non-Fermi liquid phase. We further study
the fate of the system within the superconducting phase and find that the
expected ground state, away from the critical point, is a mixed singlet/triplet
state. Finally, we find that while at T_c the triplet and singlet transitions
are dual to one another, below T_c the duality is broken, with the triplet
state more susceptible to orbital fluctuations just by virtue of its symmetry.
Our results indicate that such fluctuation-induced mixed states may be an
inherent feature of strongly correlated materials.
更多查看译文
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要