Flat-band tuning and emergent itinerant magnetism in Sr(Co1-X PdX)2As2

• 成果类型: Article
• 署名作者: Pakhira, Santanu; Lee, Yongbin; Kundu, Asish K.; Islam, Farhan; Ning, Zhenhua; Smetana, Volodymyr; Mudring, Anja-Verena; Heitmann, Thomas; Vescovo, Elio; Ke, Liqin; Vaknin, David; Johnston, David C.
• 署名单位: Iowa State University; United States Department of Energy (DOE); Ames National Laboratory; National Institute of Technology (NIT System); Maulana Azad National Institute of Technology Bhopal; United States Department of Energy (DOE); Brookhaven National Laboratory; United States Department of Energy (DOE); Brookhaven National Laboratory; Iowa State University; University of Missouri System; University of Missouri Columbia
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2519523122
• 发表日期: 2025-12-23
• 页码: e2519523122
• 关键词: flat-band physics; itinerant magnetism; Stoner mechanism; helical magnetic order; superconductivity

摘要

The interplay between magnetism and flat-band (FB) instability is a central theme in quantum materials research. A striking example is the emergence of magnetic order in a nominally nonmagnetic compound when a flat band is tuned near the Fermi energy (EF). In this study, we investigate this phenomenon in the Pauli EF. Remarkably, a minute substitution of the nonmagnetic element Pd onto the Co site (similar to 2%) induces antiferromagnetic order with a transition temperature as high as TN = 25 K. Temperature- and magnetic-field-dependent magnetic and band structure calculations demonstrate that electron doping shifts the flat band substitution with nonmagnetic elements is a unique phenomenon that underscores the pivotal role of flat-band instability in tuning magnetism in itinerant systems.