Quantum decoherence by magnetic fluctuations in a magnetic topological insulator
Abstract In magnetic topological insulators, spontaneous time-reversal symmetry breaking by intrinsic magnetic order can gap the topological surface spectrum, resulting in exotic properties like axion electrodynamics, the quantum anomalous Hall effect, and other topological magnetoelectric responses...
Saved in:
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-07-01
|
| Series: | npj Quantum Materials |
| Online Access: | https://doi.org/10.1038/s41535-025-00795-y |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849767025102028800 |
|---|---|
| author | Ruben Saatjian Simon Dovrén Kohtaro Yamakawa Ryan S. Russell James G. Analytis John W. Harter |
| author_facet | Ruben Saatjian Simon Dovrén Kohtaro Yamakawa Ryan S. Russell James G. Analytis John W. Harter |
| author_sort | Ruben Saatjian |
| collection | DOAJ |
| description | Abstract In magnetic topological insulators, spontaneous time-reversal symmetry breaking by intrinsic magnetic order can gap the topological surface spectrum, resulting in exotic properties like axion electrodynamics, the quantum anomalous Hall effect, and other topological magnetoelectric responses. Understanding the magnetic order and its coupling to topological states is essential to harness these properties. Here, we leverage near-resonant magnetic dipole optical second harmonic generation to probe magnetic fluctuations in the candidate axion insulator EuSn2(As,P)2 across its antiferromagnetic phase boundary. We observe a pronounced dimensional crossover in the quantum decoherence induced by magnetic fluctuations, whereby two-dimensional in-plane ferromagnetic correlations at high temperatures give way to three-dimensional long-range order at the Néel temperature. We also observe the breaking of rotational symmetry within the long-range-ordered antiferromagnetic state and map out the resulting spatial domain structure. More generally, we demonstrate the unique capabilities of nonlinear optical spectroscopy to study quantum coherence and fluctuations in magnetic quantum materials. |
| format | Article |
| id | doaj-art-dd1d59e2fa2c406e8cbe6781f040632a |
| institution | DOAJ |
| issn | 2397-4648 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | npj Quantum Materials |
| spelling | doaj-art-dd1d59e2fa2c406e8cbe6781f040632a2025-08-20T03:04:22ZengNature Portfolionpj Quantum Materials2397-46482025-07-011011610.1038/s41535-025-00795-yQuantum decoherence by magnetic fluctuations in a magnetic topological insulatorRuben Saatjian0Simon Dovrén1Kohtaro Yamakawa2Ryan S. Russell3James G. Analytis4John W. Harter5Materials Department, University of CaliforniaMaterials Department, University of CaliforniaDepartment of Physics, University of CaliforniaMaterials Department, University of CaliforniaDepartment of Physics, University of CaliforniaMaterials Department, University of CaliforniaAbstract In magnetic topological insulators, spontaneous time-reversal symmetry breaking by intrinsic magnetic order can gap the topological surface spectrum, resulting in exotic properties like axion electrodynamics, the quantum anomalous Hall effect, and other topological magnetoelectric responses. Understanding the magnetic order and its coupling to topological states is essential to harness these properties. Here, we leverage near-resonant magnetic dipole optical second harmonic generation to probe magnetic fluctuations in the candidate axion insulator EuSn2(As,P)2 across its antiferromagnetic phase boundary. We observe a pronounced dimensional crossover in the quantum decoherence induced by magnetic fluctuations, whereby two-dimensional in-plane ferromagnetic correlations at high temperatures give way to three-dimensional long-range order at the Néel temperature. We also observe the breaking of rotational symmetry within the long-range-ordered antiferromagnetic state and map out the resulting spatial domain structure. More generally, we demonstrate the unique capabilities of nonlinear optical spectroscopy to study quantum coherence and fluctuations in magnetic quantum materials.https://doi.org/10.1038/s41535-025-00795-y |
| spellingShingle | Ruben Saatjian Simon Dovrén Kohtaro Yamakawa Ryan S. Russell James G. Analytis John W. Harter Quantum decoherence by magnetic fluctuations in a magnetic topological insulator npj Quantum Materials |
| title | Quantum decoherence by magnetic fluctuations in a magnetic topological insulator |
| title_full | Quantum decoherence by magnetic fluctuations in a magnetic topological insulator |
| title_fullStr | Quantum decoherence by magnetic fluctuations in a magnetic topological insulator |
| title_full_unstemmed | Quantum decoherence by magnetic fluctuations in a magnetic topological insulator |
| title_short | Quantum decoherence by magnetic fluctuations in a magnetic topological insulator |
| title_sort | quantum decoherence by magnetic fluctuations in a magnetic topological insulator |
| url | https://doi.org/10.1038/s41535-025-00795-y |
| work_keys_str_mv | AT rubensaatjian quantumdecoherencebymagneticfluctuationsinamagnetictopologicalinsulator AT simondovren quantumdecoherencebymagneticfluctuationsinamagnetictopologicalinsulator AT kohtaroyamakawa quantumdecoherencebymagneticfluctuationsinamagnetictopologicalinsulator AT ryansrussell quantumdecoherencebymagneticfluctuationsinamagnetictopologicalinsulator AT jamesganalytis quantumdecoherencebymagneticfluctuationsinamagnetictopologicalinsulator AT johnwharter quantumdecoherencebymagneticfluctuationsinamagnetictopologicalinsulator |