Quantum Breakthrough Could Propel Superconductors to the Next Level

By Rice University November 3, 2024

Collected at: https://scitechdaily.com/quantum-breakthrough-could-propel-superconductors-to-the-next-level/

Researchers uncover novel magnetic and electronic properties in thin films of kagome magnets.

Physicists at Rice University and their collaborators have made a discovery that sheds new light on magnetism and electronic interactions in advanced materials, with the potential to transform technologies like quantum computing and high-temperature superconductors.

Led by Zheng Ren and Ming Yi, the research team’s study on iron-tin (FeSn) thin films reshapes scientific understanding of kagome magnets — materials named after an ancient basket-weaving pattern and structured in a unique, latticelike design that can create unusual magnetic and electronic behaviors due to the quantum destructive interference of the electronic wave function.

The findings, published in Nature Communications, reveal that FeSn’s magnetic properties arise from localized electrons, not the mobile electrons scientists previously thought. This discovery challenges existing theories about magnetism in kagome metals in which itinerant electrons were assumed to drive magnetic behavior. By providing a new perspective on magnetism, the research team’s work could guide the development of materials with tailored properties for advanced tech applications such as quantum computing and superconductors.

Impact on Quantum Materials Research

“This work is expected to stimulate further experimental and theoretical studies on the emergent properties of quantum materials, deepening our understanding of these enigmatic materials and their potential real-world applications,” said Yi, an associate professor of physics and astronomy and Rice Academy Senior Fellow.

Using an advanced technique that combines molecular beam epitaxy and angle-resolved photoemission spectroscopy, the researchers created high-quality FeSn thin films and analyzed their electronic structure. They found that even at elevated temperatures, the kagome flat bands remained split, an indicator that localized electrons drive magnetism in the material. This electron correlation effect adds a new layer of complexity to understanding how electron behavior influences magnetic properties in kagome magnets.

Selective Band Renormalization and Electron Correlations

The study also revealed that some electron orbitals showed stronger interactions than others, a phenomenon known as selective band renormalization previously observed in iron-based superconductors, offering a fresh perspective on how electron interactions influence the behavior of kagome magnets.

“Our study highlights the complex interplay between magnetism and electron correlations in kagome magnets and suggests that these effects are non-negligible in shaping their overall behavior,” said Ren, a Rice Academy Junior Fellow.

Beyond advancing the understanding of FeSn, the research has broader implications for materials with similar properties. Insights into flat bands and electron correlations could influence the development of new technologies such as high-temperature superconductors and topological quantum computation, where the interplay of magnetism and topological flat bands generates quantum states that can be used as quantum logic gates.

Reference: “Persistent flat band splitting and strong selective band renormalization in a kagome magnet thin film” by Zheng Ren, Jianwei Huang, Hengxin Tan, Ananya Biswas, Aki Pulkkinen, Yichen Zhang, Yaofeng Xie, Ziqin Yue, Lei Chen, Fang Xie, Kevin Allen, Han Wu, Qirui Ren, Anil Rajapitamahuni, Asish K. Kundu, Elio Vescovo, Junichiro Kono, Emilia Morosan, Pengcheng Dai, Jian-Xin Zhu, Qimiao Si, Ján Minár, Binghai Yan and Ming Yi, 30 October 2024, Nature Communications.
DOI: 10.1038/s41467-024-53722-3