Recently, Linjun Xie, an undergraduate student at Tianjin University of Technology (TUT), achieved research breakthroughs under the guidance of the Quantum Materials Physics and Applications Team from the School of Science. Her research paper, titled “Tunable multiple-state polarized antiferromagnets”, was published in Physical Review B - an international journal in physics and also a Nature Index journal. Xie is the first author of the paper, with Associate Professor Xiaofang Chen and Professor Jingshan Qi as corresponding authors.

In this study, they proposed a novel material system called “multiple-state polarized antiferromagnets (PAFMs)” and predicted the electric field-tunable ferromagnetism-like spin splitting. The findings provide critical theoretical support for developing multi-state information storage and multifunctional spintronic devices.

To tackle long-standing challenges in the field, known as “difficulty in lifting band spin degeneracy in traditional antiferromagnets and controlling spin splitting in altermagnets”, the research team developed a symmetry-based design strategy. By combining two key aspects, namely, “spatial inversion symmetry breaking (to ensure ferroelectricity)” and “low interface symmetry (to construct multiple potential wells)”, they designed an antiferromagnetic material system capable of achieving multiple polarization states. Notably, the energy barrier for polarization state transition in this system is comparable to that of typical ferroelectric oxides, confirming its experimental feasibility and laying a solid foundation for future device fabrication.

This achievement traces back to TUT’s College Student Innovation and Entrepreneurship Training Program, specifically the project “Physical Principles and Device Design of Non-Volatile Multi-Polarization States based on Ionic Ferroelectrics and Sliding Ferroelectrics”. Through such research-driven initiatives, TUT encourages undergraduates to engage in cutting-edge studies led by faculty supervisors, effectively fostering their scientific innovation capabilities. During her undergraduate studies, Xie has led and participated in multiple innovation projects, and earned some honors in competitions, including the Second Prize in the Undergraduate Group of the National Undergraduate Mathematical Modeling Competition.

The publication of this paper highlights the effectiveness of the university in cultivating innovative talents for undergraduate students and promoting discipline construction. TUT will continue to refine its student research and innovation support program, build more platforms for students to access frontier knowledge and explore uncharted academic territories, and empower more young scholars to make impactful contributions to the scientific community.