Novel dynamic scaling regime in hole-doped La2CuO4

TL;DR

This study investigates the spin dynamics of hole-doped La2CuO4, revealing a new low-temperature regime with a constant energy scale and discussing its connection to quantum criticality in 2D antiferromagnetic spin liquids.

Contribution

It reports the observation of a novel dynamic scaling regime in hole-doped La2CuO4, expanding understanding of quantum disordered states in 2D antiferromagnets.

Findings

Sharp S(omega,q) peaks at (pi,pi)

Crossover from omega/T scaling to a constant energy scale below 50K

Potential link to quantum disordered regime

Abstract

Only 3% hole doping by Li is sufficient to suppress the long-range 3-dimensional (3D) antiferromagnetic order in La2CuO4. The spin dynamics of such a 2D spin liquid state at T << J was investigated with measurements of the dynamic magnetic structure factor S(omega,q), using cold neutron spectroscopy, for single crystalline La2Cu0.94Li0.06O4. S(omega,q) peaks sharply at (pi,pi) and crosses over around 50K from omega/T scaling to a novel low temperature regime characterized by a constant energy scale. The possible connection to a crossover from the quantum critical to the quantum disordered regime of the 2D antiferromagnetic spin liquid is discussed.