高压下ErNi_2B_2C弹性性质、电子结构和热力学性质的第一性原理研究  

First-principles study on the elastic,electronic and thermodynamic properties of ErNi_2B_2C under high pressure

作　　者：颜小珍[1] 邝小渝[1] 毛爱杰[1] 匡芳光[1] 王振华[1] 盛晓伟[1] 

机构地区：[1]四川大学原子与分子物理研究所,成都610065

出　　处：《物理学报》2013年第10期386-391,共6页Acta Physica Sinica

基　　金：国家自然科学基金青年科学基金(批准号:11104190);国家自然科学基金(批准号:11274235);高等学校博士学科点专项科研基金(批准号:20100181110086;20110181120112)资助的课题~~

摘　　要：采用密度泛函理论中的赝势平面波方法研究了高压下超导材料ErNi2B2C的弹性性质、电子结构和热力学性质.分析表明,弹性常数、体弹模量、剪切模量、杨氏模量和弹性各向异性因子的外压力效应明显.电子态密度(DOS)的计算结果显示,在费米能级(EF)处的DOS峰随外界压强的增大显著降低,由于ErNi2B2C相对较高的超导温度(Tc)起因于EF处的DOS峰,因此推测压强增大可能会降低ErNi2B2C的Tc.类似的现象在超导材料MgB2和SrAlSi中已被发现.此外,基于准谐德拜模型,对ErNi2B2C在高温高压下的热力学性质的研究表明,在一定范围内,温度和压强将对其热膨胀系数和热容产生明显的影响.The elastic,electronic and thermodynamic properties of the superconducting ErNi2B2C material at high pressure are investigated using the plane-wave pseudopotential density functional theory.The analysis shows the dependences of the elastic constants,bulk modulus,shear modulus,Young＇s modulus and elastic anisotropy factors on the applied pressure.The calculated electronic density of states（DOS）reveals that the DOS peak at the Fermi level（EF）will decrease noticeably with pressure.It can be concluded that the pressure may reduce the superconducting temperature（Tc）of ErNi2B2C since the relatively high Tc originates from the peak in the DOS.This phenomenon is also found in some other superconductors such as MgB2 and SrAlSi.Moreover,based on the quasi-harmonic Debye model,the results of the thermodynamic properties indicate that the pressure and temperature have significant influences on the thermal expansion coefficient and heat capacity.

关 键 词：高压 弹性性质 电子结构 热力学性质 

分 类 号：O469[理学—凝聚态物理]