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Title: Resonating Valence Bond States in an Electron-Phonon System
We study a simple electron-phonon model on square and triangular versions of the Lieb lattice using an asymptotically exact strong coupling analysis. At zero temperature and electron density n 1/4 1 (one electron per unit cell), for various ranges of parameters in the model, we exploit a mapping to the quantum dimer model to establish the existence of a spin-liquid phase with Z(2) topological order (on the triangular lattice) and a multicritical line corresponding to a quantum critical spin liquid (on the square lattice). In the remaining part of the phase diagram, we find a host of charge-density-wave phases (valence-bond solids), a conventional s-wave superconducting phase, and with the addition of a small Hubbard U to tip the balance, a phonon-induced d-wave superconducting phase. Under a special condition, we find a hidden pseudospin SUo2 thorn symmetry that implies an exact constraint on the superconducting order parameters.  more » « less
Award ID(s):
2000987
PAR ID:
10509906
Author(s) / Creator(s):
;
Publisher / Repository:
Physical Review Letters
Date Published:
Journal Name:
Physical Review Letters
Volume:
130
Issue:
18
ISSN:
0031-9007
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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