Tailoring the electronic states of topological materials compatible with compound semiconductors

The discovery of topological materials compatible with semiconductors is a holy grail for quantum information science. For example, non-trivial topologies are predicted for III-V-Bi alloys with tailored polytypes or sufficiently high Bi compositions. In addition, combining  topological insulators with topological semimetals is promising for generating correlated quantum matter based upon Fermi level alignment with band extrema. Here, we discuss the influence of Bi alloying on the valence band structure of GaAs.  In addition to quantifying Bi-induced valence band shifts, we identify the key role of p-orbitals in Bi-enhanced spin-orbit splitting [1]. In addition, for antimony telluride homologous superlattices containing 2 to 4 layers of antimonene, we demonstrate the presence of a saddle point and associated van Hove singularity near the M-point.  We identify the key role of pz orbital hybridization in driving the van Hove singularity toward the Fermi level [2]. 

 

1. "Influence of Bi alloying on GaAs valence band structure", Phys. Rev. Mat. 9, 124606 (2025).

2. "Evolution of the Saddle Point in Antimony Telluride Homologous Superlattices", Phys. Rev. Mat., in press (2026).

 

Brief Bio:

 

Rachel S. Goldman is the Maria Goeppert Mayer Collegiate Professor of Materials Science and Engineering, Physics, and EECS at the University of Michigan. She is the Director of the UM Materials Research Science and Engineering Center and leads a Multidisciplinary University Research Initiative supported by the Air Force Office of Scientific Research. In addition, she serves as an Associate Editor for the Journal of Applied Physics and as elected Councilor for the Division of Materials Physics of the American Physical Society. 

 

Goldman received degrees from UM (B.S. Physics), Cornell University (M.S. Applied Physics), and the University of California, San Diego (PhD Materials Science).  Following her PhD, she was a postdoctoral fellow at Carnegie Mellon University prior to returning to UM as the Dow Corning Assistant Professor. She spent a sabbatical year as the Augustus Anson Whitney Fellow at the Radcliffe Institute at Harvard University. At UM, she has served as the Graduate Chair of Materials Science and Engineering (2008-2012) and as Associate Director of the Applied Physics Program (2010-2025). Goldman is a Fellow of the APS, the AVS, and the American Association for the Advancement of Science.