Multi-modal spectroscopy of order parameter distributions

TL;DR

This paper introduces a multi-modal spectroscopic method that independently measures charge and spin degrees of freedom in strongly correlated materials, revealing detailed interaction distributions and aiding the understanding of phase transitions.

Contribution

The work presents a novel spectroscopic paradigm capable of independently quantifying charge and spin interactions and their distributions in complex quantum materials.

Findings

Able to measure charge DOF via quadrupolar interactions even with magnetic noise

Quantifies interaction strengths and their distributions, including cases with zero average interaction

Provides protocols for directly measuring disorder distributions to understand phase transitions

Abstract

We present a multi-modal spectroscopic paradigm that enables independent measurement of charge and spin degrees of freedom (DOF) in strongly correlated materials. This spin-based technique probes symmetry-specific Hamiltonian parameters by analyzing how the time delay between applied pulses ($\tau$) affects the response. We demonstrate ways in which charge DOF that couple through the quadrupolar interaction (inversion symmetric) can be independently measured even in the presence of large magnetic noise (inversion asymmetric). The method quantifies both the strength of the interactions and its distribution (noise). We provide protocols to directly and independently measure the distribution of interaction strengths, even when the average value of the interaction is zero. By independently measuring distributions of different forms of disorder, this methodology can elucidate which microscopic symmetry drives a phase transition. We discuss potential applications to study complex phase transitions in strongly interacting quantum materials.