Experimental and theoretical P-V-T equation of state for Os 2 B 3
Experimental and theoretical P-V-T equation of state for Os 2 B 3
复制标题
Os 2 B 3 的实验和理论 P-V-T 状态方程
DOI：
10.1080/08957959.2020.1858821
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发表时间：
2020
影响因子：
2
通讯作者：
Vohra, Yogesh K.
中科院分区：
文献类型：
--
作者：
Burrage, Kaleb C.;Lin, Chia-Min;Chen, Wei-Chih;Chen, Cheng-Chien;Vohra, Yogesh K.
在准静水和等温条件下，研究了过渡金属硼化物Os2B3在巴黎-爱丁堡槽中的热弹性行为，其压力为5.4 GPa1273 K。用原位能量色散X射线衍射法测定了六方晶体结构的晶面间距，并用温度修正后的三级Birch-Murnaghan状态方程拟合出p-V-Tdata以确定热弹性常数。当从室温P-V曲线的一阶压力导数保持到K0‘= 4.0时，体积弹性系数为K0= 402 ± 21 Gpa。在二次拟合下，热膨胀系数确定为BEK−1、K−2和K。用密度泛函理论(DFT)和准谐近似(QHA)方法研究了Os2B3的ITSP-V-T曲线、声子谱、体弹性模量、比热、热膨胀和Grüneisen参数。第一性原理理论和实验观测之间取得了很好的一致性，突出了本研究中采用的Armiento-Mattsson 2005广义梯度近似泛函和QHA描述Os2B3热力学性质的成功。
Thermoelastic behavior of transition metal boride Os2B3was studied under quasi-hydrostatic and isothermal conditions in a Paris-Edinburgh cell to 5.4 GPa and 1273 K.In-situEnergy Dispersive X-ray diffraction was used to determine interplanar spacings of the hexagonal crystal structure and theP-V-Tdata were fitted to a 3rd Order Birch–Murnaghan equation of state with a temperature modification to determine thermal elastic constants. The bulk modulus was shown to beK0= 402 ± 21 GPa when the first pressure derivative was held toK0’= 4.0 from the room temperatureP-Vcurve. Under a quadratic fit, the thermal expansion coefficients were determined to beK−1,K−2, andK. Density functional theory (DFT) with the quasi-harmonic approximation (QHA) were employed to study Os2B3, including itsP-V-Tcurves, phonon spectra, bulk modulus, specific heat, thermal expansion, and the Grüneisen parameter. A good agreement between the first-principle theory and experimental observations was achieved, highlighting the success of the Armiento-Mattsson 2005 generalized gradient approximation functional employed in this study and QHA for describing thermodynamic properties of Os2B3.