title: BaGe6 and BaGe(6-x): incommensurately ordered vacancies as electron traps.
abstract: We report the high-pressure high-temperature synthesis of the germanium-based framework compounds BaGe6 (P = 15 GPa, T = 1073 K) and BaGe(6-x) (P = 10 GPa, T = 1073 K) which are metastable at ambient conditions. In BaGe(6-x), partial fragmentation of the BaGe6 network involves incommensurate modulations of both atomic positions and site occupancy. Bonding analysis in direct space reveals that the defect formation in BaGe(6-x) is associated with the establishment of free electron pairs around the defects. In accordance with the electron precise composition of BaGe(6-x) for x = 0.5, physical measurements evidence semiconducting electron transport properties which are combined with low thermal conductivity.
authors.affiliation: Max-Planck-Institut für Chemische Physik fester Stoffe , Nöthnitzer Straße 40, 01187 Dresden, Germany.
authors.forename: Lev
authors.initials: L
authors.lastname: Akselrud
authors.forename: Aron
authors.initials: A
authors.lastname: Wosylus
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Castillo
authors.forename: Umut
authors.initials: U
authors.lastname: Aydemir
authors.forename: Yurii
authors.initials: Y
authors.lastname: Prots
authors.forename: Walter
authors.initials: W
authors.lastname: Schnelle
authors.forename: Yuri
authors.initials: Y
authors.lastname: Grin
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schwarz