CAJ | 학술논문

利用晶体结构预测软件USPEX找到了一种Bi的高压稳定相 C4，其空间群是：。采用投影缀加平面波方法和广义梯度近似的第一性原理计算，研究了该新结构和 Bi 的 A7结构、高压下的单斜结构（Bi-Ⅱ相）、Host-guest结构（Bi-Ⅲ相）和bcc结构（Bi-Ⅴ相）在不同压强下的压缩行为。拟合出了状态方程，得到各相之间的能量压力关系，进而分析了各相发生相变时的压强。对比发现：常压下 C4结构与 bcc 结构的能量非常接近，前者仅仅比后者低103 eV/atom。随着压强的升高，发现在50 GPa时 C4结构比bcc结构的能量低102 eV/atom。运用基于密度泛函微扰理论的赝势平面波方法的 ESPRESSO 软件包，计算了 C4结构与 bcc 结构在10 GPa压强下的电声耦合常数，从而推算出两者相应的超导转变温度分别是5.8 K和7.4 K。另外发现两者随着压强的升高而均呈现降低的趋势，在50 GPa时， C4结构与bcc结构的分别是1.5 K和1.8 K。
이용정체결구예측연건USPEX조도료일충Bi적고압은정상 C4，기공간군시：。채용투영철가평면파방법화엄의제도근사적제일성원리계산，연구료해신결구화 Bi 적 A7결구、고압하적단사결구（Bi-Ⅱ상）、Host-guest결구（Bi-Ⅲ상）화bcc결구（Bi-Ⅴ상）재불동압강하적압축행위。의합출료상태방정，득도각상지간적능량압력관계，진이분석료각상발생상변시적압강。대비발현：상압하 C4결구여 bcc 결구적능량비상접근，전자부부비후자저103 eV/atom。수착압강적승고，발현재50 GPa시 C4결구비bcc결구적능량저102 eV/atom。운용기우밀도범함미우이론적안세평면파방법적 ESPRESSO 연건포，계산료 C4결구여 bcc 결구재10 GPa압강하적전성우합상수，종이추산출량자상응적초도전변온도분별시5.8 K화7.4 K。령외발현량자수착압강적승고이균정현강저적추세，재50 GPa시， C4결구여bcc결구적분별시1.5 K화1.8 K。
By using the algorithm implanted in USPEX code, a stable orthorhombic C4 structure (S. G.:) of Bismuth is found in high pressure. The compression behaviors of the C4 structure as well as the A7 structure, the monoclinic Bi-Ⅱ, the complex incommensurate host-guest Bi-Ⅲand the bcc Bi-Ⅴunder different pressure are calculated. The equation of states and the phase transitions among the structures are obtained. It is found that the structure at ambient pressure resembles the bcc structure with the former having enthalpy only 10 3 eV/atom lower than that of the latter. As pressure is increased to 50GPa, the enthalpy difference becomes to 10 2 eV/atom. The electron-phonon coupling (EPC) parameter of the C4 and bcc structure under different pressure are calculated, revealing the critical temperatures of superconductivity ( ) of the C4 and bcc structures is 5.8 K and 7.4 K, at ambient pressure and, when the pressure increases to 50 GPa, the temperature becomes 1.5 K and 1.8 K.