Cubic phases of BCN; A First-principles study

立方晶BCN; 第一原理計算

Kim, E.*; Pang, T.*; 内海 渉; Solozhenko, V. L.*; Zhao, Y.*

Kim, E.*; Pang, T.*; Utsumi, Wataru; Solozhenko, V. L.*; Zhao, Y.*

立方晶BCNについて、実験で得られている異なった2つの相の理解のため、第一原理に基づく理論研究を行った。理論においても立方晶相は安定であり、各々の体積弾性率の値も実験と良い一致を見た。高密度相はC-C結合の存在によって特徴づけられるのに対し、低密度相にはC-C結合が存在しない。体積弾性率など各立方晶BCNの特性は、その中に存在する電子構造や化学結合に起因している。

First-principles calculations are performed and analyzed to identify different cubic phases of BCN synthesized experimentally. With a proper choice of the supercell, cutoff energy, and sampling points, the cubic phases are found to be stable theoretically. The bulk modulus from elastic stiffness constants for each of the phases is in excellent agreement with available experimental data. The high-density phases are characterized by the existence of C-C bonds, whereas the low-density phase is characterized by the absence of C-C bonds. From the calculated equation of state and the available experimental data, we show that the unique feature of each of the cubic BCN phases is a direct result of the corresponding local electronic structure and chemical bonding in the system.