# Quantum criticality in the coupled two-leg spin ladder Ba2CuTeO6

## TL;DR

This study investigates quantum critical behavior in Ba2CuTeO6 using various spectroscopic techniques, revealing a crossover from paramagnetic to ordered states and identifying signatures of quantum criticality.

## Contribution

It provides experimental evidence of quantum criticality in a coupled spin ladder system through multiple spectroscopic methods.

## Key findings

- Successive magnetic state crossover observed
- T-linear scaling in Raman response indicates quantum criticality
- Proximity to a quantum critical point confirmed

## Abstract

We report on zero-field muon spin rotation, electron spin resonance and polarized Raman scattering measurements of the coupled quantum spin ladder Ba2CuTeO6. Zero-field muon spin rotation and electron spin resonance probes disclose a successive crossover from a paramagnetic through a spin-liquid-like into a magnetically ordered state with decreasing temperature. More significantly, the two-magnon Raman response obeys a T-linear scaling relation in its peak energy, linewidth and intensity. This critical scaling behavior presents an experimental signature of proximity to a quantum critical point from an ordered side in Ba2CuTeO6.