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本文对Гинзбург-Ландау(ГЛ)方程的微观推导所需要的条件进行了分析。分析结果表明,对于Pippard型甚至是中间型超导体,ГЛ方程有效的温度范围都是相当狭窄的。为便于研究临界温度Tc附近比较宽的范围内,强磁场中各类超导体的性质,我们从Горьков的超导普遍方程出发,利用磁场存在时“正常金属格临函数”的非局域展式,导出了一个包含能隙函数和矢势的积分微分方程组。所得的方程对London型、中间型和Pippard型超导体在△t=(Tc-T)/Tc《1的温度区域中都同样适用。利用这个方程组,我们讨论了恒定外磁场中的半无限大超导体,给出了能隙函数和穿透深度的积分表达式。在London和Pippard两个极限下,积分被解析地作出了。对于Pippard型超导体,我们在Tc附近整个温度区域计算了能隙函数和穿透深度随磁场的变化。所得的结果表明,Pippard型超导体在磁场中的行为与ГЛ理论的预言有显著的不同。The necessary conditions in the microscopic derivation of the Ginzburg-Landau (GL) equations are discussed, by showing that for a Pippard-or an intermediate-type superconductor the GL equations are valid only in a rather narrow region. Basing on the Gorkov equations for the thermodynamic Green functions of superconductor and using a nonlocal series of the "Green function of normal metal" in the magnetic field, we have derived a pair of coupled integro-differential equations for the energy-gap function and vector potential. These equations are valid for the Pippard- and intermediate-type superconductors in the same region near Tc as that for the London-type. The equations are applied to a semi-infinite superconductor in a static magnetic field. The integral expressions for energy-gap function and penetration depth are given. In the London and Pippard limit the integrals are performed analytically. For a superconductor of the Pippard-type, the corrections of energy-gap function and penetration depth due to magnetic field are calculated in the whole region near Tc. It is shown that the behaviour of a Pippard-type superconductor differs much from that predicted by the GL theory.
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