Detecting axion dynamics on the surface of magnetic topological insulators

Fuente: arXiv
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Main Authors: Gao, Zhi-Qiang, Wang, Taige, Zaletel, Michael P., Lee, Dung-Hai
Format: Preprint
Published: 2024
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author Gao, Zhi-Qiang
Wang, Taige
Zaletel, Michael P.
Lee, Dung-Hai
author_facet Gao, Zhi-Qiang
Wang, Taige
Zaletel, Michael P.
Lee, Dung-Hai
contents Axions, initially proposed to solve the strong CP problem, have recently gained attention in condensed matter physics, particularly in topological insulators. However, detecting axion dynamics has proven challenging, with no experimental confirmations to date. In this study, we identify the surface of magnetic topological insulators as an ideal platform for observing axion dynamics. The vanishing bulk gap at the surface allows for order $O(1)$ variations in the axion field, making the detection of axion-like phenomena more feasible. In contrast, these phenomena are strongly suppressed in the bulk due to the small magnetic exchange gap. We investigate two-photon decay as a signature of axion dynamics and calculate the branching ratio using a perturbative approach. Our findings reveal that the photon flux emitted from the surface is in-plane and orders of magnitude larger than that from the bulk, making it detectable with modern microwave technology. We also discuss potential material platforms for detecting axion two-photon decay and strategies to enhance the signal-to-noise ratio.
format Preprint
id arxiv_https___arxiv_org_abs_2409_17230
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Detecting axion dynamics on the surface of magnetic topological insulators
Gao, Zhi-Qiang
Wang, Taige
Zaletel, Michael P.
Lee, Dung-Hai
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
Materials Science
Axions, initially proposed to solve the strong CP problem, have recently gained attention in condensed matter physics, particularly in topological insulators. However, detecting axion dynamics has proven challenging, with no experimental confirmations to date. In this study, we identify the surface of magnetic topological insulators as an ideal platform for observing axion dynamics. The vanishing bulk gap at the surface allows for order $O(1)$ variations in the axion field, making the detection of axion-like phenomena more feasible. In contrast, these phenomena are strongly suppressed in the bulk due to the small magnetic exchange gap. We investigate two-photon decay as a signature of axion dynamics and calculate the branching ratio using a perturbative approach. Our findings reveal that the photon flux emitted from the surface is in-plane and orders of magnitude larger than that from the bulk, making it detectable with modern microwave technology. We also discuss potential material platforms for detecting axion two-photon decay and strategies to enhance the signal-to-noise ratio.
title Detecting axion dynamics on the surface of magnetic topological insulators
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2409.17230