Coexistence of Superconductivity and Superhardness in Beryllium Hexaboride Driven by Inherent Multicenter Bonding.

Title Coexistence of Superconductivity and Superhardness in Beryllium Hexaboride Driven by Inherent Multicenter Bonding.
Authors L. Wu; B. Wan; H. Liu; H. Gou; Y. Yao; Z. Li; J. Zhang; F. Gao; H.K. Mao
Journal J Phys Chem Lett
DOI 10.1021/acs.jpclett.6b02444
Abstract

Unique multicenter bonding in boron-rich materials leads to the formation of complex structures and intriguing properties. Here global structural searches are performed to unearth the structure of beryllium hexaboride (BeB6) synthesized decades ago. Three BeB6 phases (?, ?, and ?) were predicted to be stable at ambient and high pressures. The ground state at ambient pressure, ?-BeB6, consists of a strong and uniformly distributed covalent B-B network, which results in exceptional elastic properties and a hardness of 46 GPa comparable to ?-B. Even more surprisingly, ?-BeB6 retains credible electron phonon coupling in the boron sublattice, and is predicted to be superconducting at 9 K. Above 4 GPa, ?-BeB6 is stabilized with alternating boron slabs and triangular beryllium layers analogous to the structure of MgB2. The ?-BeB6 is predicted to be superconducting at 24 K, similar to Nb3(Al,Ge). The ?-BeB6 is stable above 340 GPa. The understanding of intrinsic multicenter-bonding mechanism and related properties demonstrated in the very example of BeB6 provides new insights for the design of tunable multifunctional materials.

Citation L. Wu; B. Wan; H. Liu; H. Gou; Y. Yao; Z. Li; J. Zhang; F. Gao; H.K. Mao.Coexistence of Superconductivity and Superhardness in Beryllium Hexaboride Driven by Inherent Multicenter Bonding.. J Phys Chem Lett. 2016;7(23):48984904. doi:10.1021/acs.jpclett.6b02444

Related Elements

Beryllium

See more Beryllium products. Beryllium (atomic symbol: Be, atomic number: 4) is a Block S, Group 2, Period 2 element with an atomic weight of 9.012182. Beryllium Bohr ModelThe number of electrons in each of Beryllium's shells is [2, 2] and its electron configuration is [He] 2s2. The beryllium atom has a radius of 112 pm and a Van der Waals radius of 153 pm. Beryllium is a relatively rare element in the earth's crust; it can be found in minerals such as bertrandite, chrysoberyl, phenakite, and beryl, its most common source for commercial production. Beryllium was discovered by Louis Nicolas Vauquelin in 1797 and first isolated by Friedrich Wöhler and Antoine Bussy in 1828. Elemental BerylliumIn its elemental form, beryllium has a gray metallic appearance. It is a soft metal that is both strong and brittle; its low density and high thermal conductivity make it useful for aerospace and military applications. It is also frequently used in X-ray equipment and particle physics. The origin of the name Beryllium comes from the Greek word "beryllos," meaning beryl.

Boron

See more Boron products. Boron Bohr ModelBoron (atomic symbol: B, atomic number: 5) is a Block P, Group 13, Period 2 element with an atomic weight of 10.81. The number of electrons in each of boron's shells is 2, 3 and its electron configuration is [He] 2s2 2p1. The boron atom has a radius of 90 pm and a Van der Waals radius of 192 pm. Boron was discovered by Joseph Louis Gay-Lussac and Louis Jacques Thénard in 1808 and was first isolated by Humphry Davy later that year. Boron is classified as a metalloid is not found naturally on earth. Elemental BoronAlong with carbon and nitrogen, boron is one of the few elements in the periodic table known to form stable compounds featuring triple bonds. Boron has an energy band gap of 1.50 to 1.56 eV, which is higher than that of either silicon or germanium. The name Boron originates from a combination of carbon and the Arabic word buraqu meaning borax.

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