CAJ | 학술논문

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.
채용밀도범함이론중적안세평면파방법연구료고압하초도재료ErNi2B2C적탄성성질、전자결구화열역학성질.분석표명,탄성상수、체탄모량、전절모량、양씨모량화탄성각향이성인자적외압력효응명현.전자태밀도(DOS)적계산결과현시,재비미능급(EF)처적DOS봉수외계압강적증대현저강저,유우ErNi2B2C상대교고적초도온도( Tc)기인우EF처적DOS봉,인차추측압강증대가능회강저ErNi2B2C적Tc.유사적현상재초도재료MgB2화SrAlSi중이피발현.차외,기우준해덕배모형,대ErNi2B2C재고온고압하적열역학성질적연구표명,재일정범위내,온도화압강장대기열팽창계수화열용산생명현적영향.
@@@@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.