Linear Decomposition of Atomic Orbitals: Mapping the Electronic Properties of Crystalline Materials

Dylla, Maxwell Thomas

doi:https://doi.org/10.21985/n2-pkc6-bg12

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Linear Decomposition of Atomic Orbitals: Mapping the Electronic Properties of Crystalline Materials

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An extensive set of functional electronic properties depends on the electronic structure. These properties are directly connected to the reciprocal-space representation of electronic structure. However, there is a complementary, real-space perspective that is described by combinations of atomic orbitals. Atomic orbitals are the components of electronic structures, analogous to how elements are the components of crystal structures. To further the analogy, relevant portions of the electronic structure are described by atomic orbital compositions. Within a material family, the atomic orbital compositions can explain the variety of electronic structures ex- pressed by each phase. An orbital phase diagram, which maps each phase according to its atomic orbital com- position, can differentiate different classes of electronic structure. In thermoelectric applications, the relevant portions of the electronic structure are the valence and conduction band edges (the highest-performing mate- rials are semiconductors). The location, shape, and number of carrier pockets near the band edge determine their transport properties. In light of recent developments in structure-matching algorithms, which can group databases of electronic structure calculations into material families, the orbital phase diagram approach will be useful for identifying promising candidate materials within different structure families. However, since many materials are synthesized as polycrystalline samples, it is important to identify whether the measured properties are a result of the intrinsic electronic structure or micro-structural defects. In particular, grain boundaries can confound the interpretation of the transport properties.

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