Valentine AJS, Talapin DV, Mazziotti DA. Orbitals, Occupation Numbers, and Band Structure of Short One-Dimensional Cadmium Telluride Polymers.
J Phys Chem A 2017;
121:3142-3147. [PMID:
28406638 DOI:
10.1021/acs.jpca.7b00858]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recent work found that soldering CdTe quantum dots together with a molecular CdTe polymer yielded field-effect transistors with much greater electron mobility than quantum dots alone. We present a computational study of the CdTe polymer using the active-space variational two-electron reduced density matrix (2-RDM) method. While analogous complete active-space self-consistent field (CASSCF) methods scale exponentially with the number of active orbitals, the active-space variational 2-RDM method exhibits polynomial scaling. A CASSCF calculation using the (48o,64e) active space studied in this paper requires 1024 determinants and is therefore intractable, while the variational 2-RDM method in the same active space requires only 2.1 × 107 variables. Natural orbitals, natural-orbital occupations, charge gaps, and Mulliken charges are reported as a function of polymer length. The polymer, we find, is strongly correlated, despite possessing a simple sp3-hybridized bonding scheme. Calculations reveal the formation of a nearly saturated valence band as the polymer grows and a charge gap that decreases sharply with polymer length.
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