title: Probing the out-of-plane distortion of single point defects in atomically thin hexagonal boron nitride at the picometer scale.
abstract: Crystalline systems often lower their energy by atom displacements from regular high-symmetry lattice sites. We demonstrate that such symmetry lowering distortions can be visualized by ultrahigh resolution transmission electron microscopy even at single point defects. Experimental investigation of structural distortions at the monovacancy defects in suspended bilayers of hexagonal boron nitride (h-BN) accompanied by first-principles calculations reveals a characteristic charge-induced pm symmetry configuration of boron vacancies. This symmetry breaking is caused by interlayer bond reconstruction across the bilayer h-BN at the negatively charged boron vacancy defects and results in local membrane bending at the defect site. This study confirms that boron vacancies are dominantly present in the h-BN membrane.
authors.affiliation: Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: Nasim
authors.initials: N
authors.lastname: Alem
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Yazyev
authors.forename: Christian
authors.initials: C
authors.lastname: Kisielowski
authors.forename: P
authors.initials: P
authors.lastname: Denes
authors.forename: Ulrich
authors.initials: U
authors.lastname: Dahmen
authors.forename: Peter
authors.initials: P
authors.lastname: Hartel
authors.forename: Maximilian
authors.initials: M
authors.lastname: Haider
authors.forename: Maarten
authors.initials: M
authors.lastname: Bischoff
authors.forename: Bin
authors.initials: B
authors.lastname: Jiang
authors.forename: Steven G
authors.initials: SG
authors.lastname: Louie
authors.forename: A
authors.initials: A
authors.lastname: Zettl