Spin-gapped incoherent metal with preformed pairing in the doped antiferromagnetic Mott insulator

Abstract

We investigate how the antiferromagnetic Mott insulator evolves into the d-wave BCS superconductor through hole doping. Allowing spin fluctuations in the strong coupling approach, we find a spin-gapped incoherent metal with preformed pairing as an intermediate phase between the antiferromagnetic Mott insulator and d-wave superconductor. This non-Fermi liquid metal is identified with an infrared stable fixed point in the spin-decomposition gauge theory, analogous to the spin liquid insulator in the slave-boson gauge theory. We consider the single particle spectrum and dynamical spin susceptibility in the anomalous metallic phase, and discuss physical implications.

Quantum Boltzmann equation study for the Kondo breakdown quantum critical point

“…One can obtain this effective field theory from the Hubbard model in the frustrated lattice based on the U (1) slave-rotor representation [21], where charge fluctuations are gapped at half filling, but magnetic ordering is prohibited owing to the geometrical frustration, corresponding to a spin liquid Mott insulator. One also finds this effective field theory in the so called algebraic charge liquid for the anomalous normal state of high T c cuprates, derived from the U (1) slave-fermion representation, where spin fluctuations described by Schwinger bosons are gapped, but charged excitations represented by fermionic holons are gapless, allowing an anomalous metallic state due to scattering with gauge fluctuations [22,23].…”