Abstract
We describe the phases of a solvable model of electrons with infinite-range, and random, hopping, and exchange interactions, similar to those in the Sachdev-Ye-Kitaev models. The electron fractionalizes, as in an “orthogonal metal,” into a fermion , which carries both the electron spin and charge, and a boson . Both and carry emergent gauge charges. The model has a phase in which the bosons are gapped, and the fermions are gapless and critical, and so the electron spectral function is gapped. This phase can be considered as a toy model for the underdoped cuprates, without spatial structure. The model also has an extended, critical, “quasi-Higgs” phase where both and are gapless, and the electron operator has a Fermi liquid-like propagator in imaginary time, . So while the electron spectral function has a Fermi liquid form, other properties are controlled by fractionalization and the anomalous exponents of the and excitations. This quasi-Higgs phase is proposed as a toy model of the overdoped cuprates. We also describe the critical state separating these two phases.
2 More- Received 18 April 2018
- Revised 16 July 2018
DOI:https://doi.org/10.1103/PhysRevB.98.075150
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