Quantum critical point with competing propagating and diffusive spin excitations

TL;DR

This paper investigates a quantum critical point in itinerant spin systems, revealing a complex interplay between propagating and diffusive spin excitations that explains observed scaling behaviors in cuprate superconductors.

Contribution

It introduces a model incorporating feedback effects of spin fluctuations, showing how correlation length dependent damping leads to non-trivial dynamical scaling.

Findings

Correlation length dependent spin damping observed

Dynamical scaling with z≈1 explained

Quantitative match with underdoped cuprate data

Abstract

Feedback effects due to spin fluctuation induced precursors in the fermionic quasiparticle spectrum are taken into account in the description of a quantum critical point of itinerant spin systems. A correlation length dependent spin damping occurs, leading to a dynamical scaling with z\approx 1 which non-trivially competes with the conventional spin wave behavior. We obtain, within a one loop renormalization group approach, a quantitative explanation for the scaling behavior seen in underdoped cuprate superconductors.