Emergent Strange Nodal Metallicity from Orbital-Selective Mott Physics

TL;DR

This paper uses advanced computational methods to connect strange metallic behavior in unconventional superconductors to orbital-selective Mott physics, revealing unique spin and charge responses and their relation to experimental observations.

Contribution

It demonstrates that strange metallicity arises from orbital-selective Mottness, providing a microscopic understanding of its origin in correlated electron systems.

Findings

Disparate spin and charge responses observed.

Fractional power-law behavior and ω/T-scaling identified.

Good agreement with experimental optical and NMR data.

Abstract

While a specific kind of strange metal is increasingly found to be the "normal" states in a wide variety of unconventional superconductors, its microscopic origin is presently a hotly debated enigma. Using dynamical mean-field theory (DMFT) based on hybridization expansion of continuous-time quantum Monte-Carlo (CTQMC) solver for an extended two-band Hubbard model (2BHM), we investigate the conditions underlying the emergence of such a metal. Specifically, we tie strange metallicity to an orbital-selective Mottness in 2BHM or momentum-selective Mott phase (OSMP) in 2D Hubbard models inspired by a cluster-to-orbital mapping. We find $(i)$ disparate spin and charge responses, $(ii)$ fractional power-law behavior and $\omega/T$-scaling in the charge and spin fluctuation responses, and $(iii)$ very good accord with optical conductivity and nuclear magnetic relaxation rates in the slightly underdoped normal states of cuprates and Fe-arsenides. We analyze the local problem using bosonization to show that such anomalous responses arise from a lattice orthogonality catastrophe specifically in the OSMP. Our work establishes the intimate link between strange metallicity and selective Mottness in quantum matter.