title: Selective Crystal Growth and Structural, Optical, and Electronic Studies of Mn3Ta2O8.
abstract: Mn3Ta2O8, a stable targeted material with an unusual and complex cation topology in the complicated Mn-Ta-O phase space, has been grown as a ≈3-cm-long single crystal via the optical floating-zone technique. Single-crystal absorbance studies determine the band gap as 1.89 eV, which agrees with the value obtained from density functional theory electronic-band-structure calculations. The valence band consists of the hybridized Mn d-O p states, whereas the bottom of the conduction band is formed by the Ta d states. Furthermore, out of the three crystallographically distinct Mn atoms that are four-, seven-, or eight-coordinate, only the former two contribute their states near the top of the valence band and hence govern the electronic transitions across the band gap.
authors.forename: Karl
authors.initials: K
authors.lastname: Rickert
authors.forename: Eric A
authors.initials: EA
authors.lastname: Pozzi
authors.forename: Rabi
authors.initials: R
authors.lastname: Khanal
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Onoue
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Trimarchi
authors.forename: Julia E
authors.initials: JE
authors.lastname: Medvedeva
authors.forename: Mark C
authors.initials: MC
authors.lastname: Hersam
authors.forename: Richard P
authors.initials: RP
authors.lastname: Van Duyne
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Poeppelmeier