无序合金中相干势近似的另一种推导——紧束缚模型

本文用Matsubara和Toyozawa的locator展开方法重新推导单粒子和双粒子格林函数的相干势近似(CPA)方程,文中不采用对累积量做自洽处理的方法来考虑原子之间的体积排斥效应,而采用Yonezawa早先提出的一种图形法,本文的重点是提出一个可以用来生成单格点图形自洽方程的系统方法,并用在处理双粒子平均格林函数上,这种处理方法可以推广到处理包括液态金属或非晶态金属等具有短程序系统电导率的CPA方程。 关键词：

AN ALTERNATIVE DERIVATION OF COHERENT-POTENTIAL APPROXIMATION FOR DISORDERED ALLOYS-TIGHT BINDING MODEL

The coherent-potential approximation (CPA) for both single-particle and two-particle Green's functions are rederived using locator expansion method proposed by Matsubara and Toyozawa. Instead of using self-contained cumulant expansion to treat the excluded volume effects for atoms, we use a diagrammatic method with the idea first proposed by Yonezawa. A systemmatic method is used to generate self-consistent equations for all single-site diagrams. We emphasis our treatment for two-particle Green's function which can be extended to obtain the corresponding CPA equation for electrical conductivity in liquid metals and amorphous solids.