Anti-doping in Insulators and Semiconductors having Intermediate Bands with Trapped Carriers

Abstract

Ordinary doping by electrons (holes) generally means that the Fermi level shifts towards the conduction band (valence band) and that the conductivity of free carriers increases. Recently, however, some peculiar doping characteristics were sporadically recorded in different materials without noting the mechanism: electron doping was observed to cause a portion of the lowest unoccupied band to merge into the valance band, leading to a decrease in conductivity. This behavior we dub as 'anti-doping' was seen in rare-earth nickel oxides SmNiO3, cobalt oxides SrCoO2.5, Li-ion battery materials and even MgO with metal vacancies. We describe the physical origin of anti-doping as well as its inverse problem, the 'design principles' that would enable intelligent search of materials. We find that electron anti-doping is expected in materials having pre-existing trapped holes and is caused by annihilation of such 'hole polarons' via electron doping. This may offer an unconventional way of controlling conductivity.

arXiv comment14 pages, 4 figures

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Cited by in corpus (7)

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• Spontaneous non-stoichiometry and ordering of metal vacancies in degenerate insulators
• High-density electron doping of SmNiO${}_3$ from first principles
• First-principles study of electron and hole doping in perovskite nickelates
• Realization of electron antidoping by modulating the breathing distortion in BaBiO${}_3$
• "Fraternal-twin" ferroelectricity: competing polar states in hydrogen-doped samarium nickelate from first principles