Quantum Noise Spectroscopy of Criticality in an Atomically Thin Magnet

Mark E. Ziffer; Francisco Machado; Benedikt Ursprung; Artur Lozovoi; Aya Batoul Tazi; Zhiyang Yuan; Michael E. Ziebel; Tom Delord; Nanyu Zeng; Evan Telford; Daniel G. Chica; Dane W. deQuilettes; Xiaoyang Zhu; James C. Hone; Kenneth L. Shepard; Xavier Roy; Nathalie P. de Leon; Emily J. Davis; Shubhayu Chatterjee; Carlos A. Meriles; Jonathan S. Owen; P. James Schuck; Abhay N. Pasupathy

arXiv · 2407.05614

Quantum Noise Spectroscopy of Criticality in an Atomically Thin Magnet

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Abstract

Dynamic critical fluctuations in magnetic materials encode important information about magnetic ordering in the associated critical exponents. Using nitrogen-vacancy centers in diamond, we implement $T_2$ (spin-decoherence) noise magnetometry to study critical dynamics in a 2D Van der Waals magnet CrSBr. By analyzing NV decoherence on time scales approaching the characteristic correlation time $\tau_c$ of critical fluctuations, we extract the critical exponent $\nu$ for the correlation length. Our result deviates from the Ising prediction and highlights the role of long-range dipolar interactions in 2D CrSBr. Furthermore, analyzing the divergence of the correlation length suggests the possibility of 2D-XY criticality in CrSBr in a temperature window near $T_C$ where static magnetic domains are absent. Our work provides a first demonstration of $T_2$ noise magnetometry to quantitatively analyze critical scaling behavior in 2D materials.

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Mark E. Ziffer, Francisco Machado, Benedikt Ursprung, Artur Lozovoi, Aya Batoul Tazi, Zhiyang Yuan, Michael E. Ziebel, Tom Delord, Nanyu Zeng, Evan Telford, Daniel G. Chica, Dane W. deQuilettes, Xiaoyang Zhu, James C. Hone, Kenneth L. Shepard, Xavier Roy, Nathalie P. de Leon, Emily J. Davis, Shubhayu Chatterjee, Carlos A. Meriles, Jonathan S. Owen, P. James Schuck, Abhay N. Pasupathy. 2024-07-08. Quantum Noise Spectroscopy of Criticality in an Atomically Thin Magnet. https://arxiv.org/abs/2407.05614

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