title: Superhard BC(3) in cubic diamond structure.
abstract: We solve the crystal structure of recently synthesized cubic BC(3) using an unbiased swarm structure search, which identifies a highly symmetric BC(3) phase in the cubic diamond structure (d-BC(3)) that contains a distinct B-B bonding network along the body diagonals of a large 64-atom unit cell. Simulated x-ray diffraction and Raman peaks of d-BC(3) are in excellent agreement with experimental data. Calculated stress-strain relations of d-BC(3) demonstrate its intrinsic superhard nature and reveal intriguing sequential bond-breaking modes that produce superior ductility and extended elasticity, which are unique among superhard solids. The present results establish the first boron carbide in the cubic diamond structure with remarkable properties, and these new findings also provide insights for exploring other covalent solids with complex bonding configurations.
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China and College of Physics, Beihua University, Jilin 132013, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
authors.forename: Hanyu
authors.initials: H
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China and College of Materials Science and Engineering, Jilin University, Changchun 130012, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Li
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
authors.forename: Yanchao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
authors.forename: Hongdong
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Physics and High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, USA.
authors.forename: Changfeng
authors.initials: C
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, China.
authors.forename: Yanming
authors.initials: Y
authors.lastname: Ma