High-Throughput Discovery of Semiconductors with Antibonding Valence Band and Bonding Conduction Band

Conventional semiconductors typically have dominant bonding states near the valence band maximum (VBM) and antibonding states near the conduction band minimum (CBM). Semiconductors with the opposite electronic configuration, namely, VBM with dominant antibonding nature and CBM with dominant bonding nature (“AVBC semiconductors” for brevity), were theoretically proposed to exhibit excellent optoelectronic properties because of defect tolerance. However, no AVBC semiconductors have been identified so far. Here, we use high-throughput computation to identify over 100 AVBC semiconductors and analyze the transition metal dichalcogenide MX2 (M = Hf, Zr; X = S, Se) family in detail. In addition to verifying their defect tolerance for both electrons and holes using first-principles simulations, we discovered that photoexcitation of charge carriers can lead to significant lattice stiffening and increased thermal conductivity, which can potentially be used as photodriven thermal switches. Our work analyzed the formation of the AVBC electronic structure and showcased the unusual photoinduced lattice dynamics.