CAJ | 학술논문

基于密度泛函理论的第一性原理方法，系统研究了三元金属间化合物SrAlSi在高压下的电子性质和晶格动力学性质。三元金属间化合物SrAlSi具有和MgB2类似的六角蜂巢状结构， Sr原子取代了Mg原子的位置， Al、Si原子无序地占据B原子的位子。通过对SrAlSi三元金属间化合物能带和三维费米面的计算，发现在压力的作用下SrAlSi费米面附近的能带发生电子拓扑变化，压力可以导致电子拓扑结构相变（ETTs）。通过晶格动力学研究发现，在压力的作用下， SrAlSi的光学支沿着A L H方向逐渐软化，声学支逐渐变硬，说明金属间化合物SrAlSi在压力作用下结构不是很稳定，随着压力的继续增大，会有新的结构出现。
기우밀도범함이론적제일성원리방법，계통연구료삼원금속간화합물SrAlSi재고압하적전자성질화정격동역학성질。삼원금속간화합물SrAlSi구유화MgB2유사적륙각봉소상결구， Sr원자취대료Mg원자적위치， Al、Si원자무서지점거B원자적위자。통과대SrAlSi삼원금속간화합물능대화삼유비미면적계산，발현재압력적작용하SrAlSi비미면부근적능대발생전자탁복변화，압력가이도치전자탁복결구상변（ETTs）。통과정격동역학연구발현，재압력적작용하， SrAlSi적광학지연착A L H방향축점연화，성학지축점변경，설명금속간화합물SrAlSi재압력작용하결구불시흔은정，수착압력적계속증대，회유신적결구출현。
Electronic and lattice dynamic properties of ternary intermetallic SrAlSi are studied with first-principles calculations based on density functional theory under high pressures. SrAlSi has a similar hexagon-honeycombed structure to MgB2 , where Sr atoms substitute Mg atoms, Al and Si atoms randomly occupy the positions of B atoms. It is found that under high pressure electronic topological transition ( ETT ) occur in the band of SrAlSi near Fermi surface. Lattice dynamics of SrAlSi are studied by phonon dispersion spectra at different pressures. The calculation shows that optical branches soften along A-L-H line and phonon modes harden with increase of pressure. It is indicated that structure of intermetallic compound SrAlSi is unstable under high pressures.