二维单层Ca_(2)N声子谱和热力学性质的第一性原理研究  

First-principles Study of Phonon Spectra and Thermodynamic Properties of 2D-monolayer Ca_(2)N

作　　者：张雷雷 王艺佳 杨保成[1] ZHANG Leilei;WANG Yijia;YANG Baocheng(Institute of Nano-Structured Functional Materials,Huanghe Science and Technology College,Zhengzhou 450063,P.R.China;Institute of Atomic and Molecular Physics,Sichuan University,Chengdu 610065,P.R.China)

机构地区：[1]黄河科技学院纳米功能材料研究所,郑州450063 [2]四川大学原子与分子物理研究所,成都610065

出　　处：《光散射学报》2022年第4期284-289,共6页The Journal of Light Scattering

基　　金：黄河科技学院博士科研启动经费(02032408);河南省高等学校重点科研项目(23A140025)。

摘　　要：开发具有优异性能的可充电二次化学电池材料是解决当今社会所面临能源危机问题的有效途径之一。钠离子电池因为具有原材料储量丰富和价格低廉的优势而被视为替代锂离子电池的最优候选材料。最近的研究表明,二维单层电子化合物Ca_(2)N是良好的钠离子电池负极候选材料。然而,当前研究多集中于块体Ca_(2)N的物性,二维单层Ca_(2)N基本物性的研究还比较缺乏。鉴于此,本工作基于第一性原理计算方法详细研究了单层Ca_(2)N的晶格振动特性,确定了其光学振动模式的频率值、简并度和对称性,并通过声子态密度展示了不同类型原子在不同频率范围的贡献大小。最后,还基于声子谱计算了该材料的声子振动自由能、熵和等体积摩尔热容量等基本热力学性质,并与单晶Ca_(2)N进行了对比分析。本工作对于实验研究者设计具有优异性能的类似结构金属离子电池负极材料具有一定参考价值和理论指导意义。One of the most effective ways to solve the energy crisis is to develop rechargeable secondary chemical battery materials with excellent performance.Because of their abundant raw material reserves and low prices,Na-ion batteries(NIB)are regarded as the best candidate materials to replace Li-ion batteries(LIB).Recent research has revealed that the layered electride Ca_(2)N is an excellent candidate for NIB electrodes.However,the current research focuses mainly on the properties of bulk Ca_(2)N,leaving the basic physical properties of monolayer Ca_(2)N lacked.Based on this,this work investigates the lattice dynamics properties of 2D-monolayer Ca_(2)N,gives the frequency values,degeneracy,and symmetry of this material’s optical vibration modes,and demonstrates the contribution of Ca and N atoms in different frequency ranges via densities of the phonon states.Finally,using the phonon spectrum,the basic thermodynamic properties of monolayer Ca_(2)N,such as phonon vibrational free energy,entropy,and heat capacity,are calculated and compared to crystal Ca_(2)N.This work has some reference value and theoretical guidance significance for experimental researchers interested in developing similar structural metal-ion battery materials with excellent performance.

关 键 词：密度泛函理论 二维单层Ca_(2)N 声子谱 热力学性质 

分 类 号：O482[理学—固体物理]