Brazhkin V V, Katayama Y, Trachenko K, Tsiok O B, Lyapin A G, Artacho Emilio, Dove M, Ferlat G, Inamura Y, Saitoh H
Institute for High Pressure Physics RAS, 142190 Troitsk Moscow region, Russia.
Phys Rev Lett. 2008 Jul 18;101(3):035702. doi: 10.1103/PhysRevLett.101.035702.
We study high-pressure polyamorphism of B2O3 glass using x-ray diffraction up to 10 GPa in the 300-700 K temperature range, in situ volumetric measurements up to 9 GPa, and first-principles simulations. Under pressure, glass undergoes two-stage transformations including a gradual increase of the first B-O (O-B) coordination numbers above 5 GPa. The fraction of boron atoms in the fourfold-coordinated state at P<10 GPa is smaller than was assumed from inelastic x-ray scattering spectroscopy data, but is considerably larger than was previously suggested by the classical molecular dynamics simulations. The observed transformations under both compression and decompression are broad in hydrostatic conditions. On the basis of ab initio results, we also predict one more transformation to a superdense phase, in which B atoms are sixfold coordinated.
我们在300 - 700 K温度范围内，利用高达10 GPa的X射线衍射、高达9 GPa的原位体积测量以及第一性原理模拟，研究了B2O3玻璃的高压多晶型现象。在压力作用下，玻璃经历两阶段转变，包括在高于5 GPa时第一B - O（O - B）配位数逐渐增加。在P < 10 GPa时，处于四重配位状态的硼原子分数小于非弹性X射线散射光谱数据所假设的值，但远大于经典分子动力学模拟先前提出的值。在静水条件下，压缩和减压过程中观察到的转变都很宽泛。基于从头算结果，我们还预测了向一种超密相的另一种转变，其中B原子为六重配位。
