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在广义梯度近似(GGA)和局域密度近似(LDA)下,采用第一性原理方法研究CuXSe2(X=B,Al,Ga,In,Tl)晶体结构的稳定性和力学性质.分析CuXSe2(X=B,Al,Ga,In,Tl)结构的晶格常数,弹性常数,体积模量,剪切模量,杨氏模量,泊松比,对比各材料的力学性质变换规律.计算结果表明,根据力学稳定判据,在零温零压下,CuXSe2(X=B,Al,Ga,In,Tl)的晶体结构是力学稳定的.经过同主族替换,发现晶格常数越大,体弹性模量就越小.这可以解释为X离子半径逐渐增大,晶格常数逐渐增加,晶体的可压缩性也增加.另外,CuTlSe2的剪切模量最小,不容易发生剪切形变.CuBSe2的杨氏模量最大,其刚度最高.由Pugh经验关系可知CuXSe2(X=B,Al,Ga,In,Tl)均属于韧性材料.
The first-principle method was used to study the stability and mechanical properties of CuXSe2 (X = B, Al, Ga, In, Tl) crystal structures under the generalized gradient approximation (GGA) and local density approximation (LDA) X = B, Al, Ga, In, Tl) structure lattice constants, elastic constants, bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio, It is shown that the crystal structure of CuXSe2 (X = B, Al, Ga, In, Tl) is mechanically stable under the condition of zero temperature and zero pressure according to the criterion of mechanical stability.After the replacement of main groups, the larger the lattice constant, The smaller the elastic modulus of the CuTlSe2, which can be explained by the gradual increase of X-ray radius, the increase of the lattice constant and the increase of the compressibility of the crystal.In addition, CuTlSe2 has the smallest shear modulus and is not prone to shear deformation. CuBSe2 has the highest Young’s modulus and the highest stiffness, and CuXSe2 (X = B, Al, Ga, In, Tl) belongs to the ductile material.