“Design of Single-Band Correlated Materials via First-Principles Theory and Materials Informatics”
Abstract: One important yet exceedingly rare property of the cuprate high-temperature superconductors is the presence of a single correlated d band at low energy, leading to the one-band Hubbard model as the minimal description. Here, in order to search for materials with interesting strong correlation physics as well as possible benchmark systems for the one-band Hubbard model, we present two approaches to find one-band correlated materials analogous to the cuprates.
In the first approach, we replace Mo with V in the well-studied monolayer MoS2. The trigonal prismatic phase of VS2, which is lower in energy than the competing octahedral phase within density functional theory, has an isolated low-energy d band due to the nominal electron count, crystal field splitting, and nearest-neighbor V-V interactions. Local correlations, solved at the mean-field level, lead to a Mott insulator. Trigonal prismatic VS2 is a promising candidate for strongly correlated electron physics that, if realized, could be experimentally probed in an unprecedented fashion due to its monolayer nature.
In the second approach, we leverage the emerging field of materials informatics. Using the half a million real and hypothetical inorganic crystals in the Open Quantum Materials Database, we search for synthesizable materials whose nominal transition metal d electron count and crystal field are compatible with achieving an isolated half-filled d band. Several Cu compounds, including bromide, oxide, selenate, and pyrophosphate chemistries, successfully achieve the one-band electronic structure; further calculations reveal substantial evidence for strong correlation physics, including Mott insulating behavior and antiferromagnetism. The success of our data-driven approach to discovering new correlated materials opens up new avenues in materials design.
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