School of Physics Fall Colloquium Series- Dr. Nitin Samarth(Penn State)

Speaker: Dr. Nitin Samarth(Penn State) 

Host: Hailong Wang

Title: Puzzles at the interface between topology, magnetism, and superconductivity  

Abstract: The confluence of fundamental symmetries (such as time reversal invariance) and spin-orbit coupling is known to produce electronic states in crystalline solids that are accurately described using the language of topology. We use the synthesis of epitaxial topological quantum materials [1] to raise interesting questions about the manifestations of bulk-boundary correspondence in two cases where topology is interfaced with ferromagnetism: quantized anomalous Hall insulators [2] and non-conserved spin currents in topological insulator/ferromagnet heterostructures [3]. Finally, we discuss the quantum technology implications of emergent superconductivity at the interface of ferromagnetism and topology [4,5].

This work is supported by the Penn State Two-Dimensional Crystal Consortium-Materials Innovation Platform (2DCC-MIP) under NSF Grant No. DMR-2039351 and by the National Science Foundation (DMR-2407130).

1. Nitin Samarth, "Quantum materials discovery from a synthesis perspective," Nature Materials 16, 1068-1076 (2017).

2. M. Ferguson et al., “Direct visualization of electronic transport in a quantum anomalous Hall insulator,” Nature Materials 22, 1100-1105 (2023).

3. Y. Ou et al., “Spin Hall conductivity in Bi1-xSbx as an experimental test of bulk-boundary correspondence,” Nano Letters 25, 8775 (2025).

4. H. Yi et al., “Interface-induced superconductivity in magnetic topological insulators,” Science 383, 634-639 (2024).

5. S. Islam et al. “Emergent superconductivity and non-reciprocal transport in a van der Waals Dirac semimetal/antiferromagnet heterostructure,” Nano Letters 26, 11671 (2026).

Bio: Nitin Samarth is the Verne M. Willaman Professor of Physics & Professor of Materials Science/Engineering at the Pennsylvania State University. He joined the Penn State faculty in 1992 and served as Downsbrough Department Head of Physics from 2011 - 2023.

Samarth has pioneered the epitaxial synthesis and nanopatterning of a variety of spin-based quantum materials, derived from both conventional and magnetic semiconductors and ferromagnetic metals, resulting in fundamental advances in semiconductor and quantum spintronics, topological spintronics, and artificial spin ice. He has published 317 papers with about 19,600 citations (Web of Science). He is a member of the American Academy of Arts and Sciences, Fellow of the American Physical Society, and Fellow of the American Association for the Advancement of Science. He received the APS Adler Lectureship Award in Materials Physics in 2024. He has also been recognized with Penn State’s Faculty Scholar Medal in the Physical Sciences and George Atherton Excellence in Teaching Award, Outstanding Physics Alumnus Award and Outstanding Science Alumnus Award from Purdue University, and an Outstanding Alumnus Award from IIT Bombay.