Open AccessELECTRON STATES OF A NORMAL-SUPERCONDUCTING MULTI-FILM STRUCTURE
Author(s) -
Xing Ding-Yu,
ChangDe Gong
Publication year - 1982
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.31.633
Subject(s) - superconductivity , condensed matter physics , materials science , thin film , electronic band structure , perpendicular , gapless playback , density of states , metal , electron , particle (ecology) , crystal structure , crystal (programming language) , physics , crystallography , quantum mechanics , geometry , nanotechnology , oceanography , mathematics , chemistry , geology , computer science , programming language , metallurgy
This work is a continuation of the ref. [1, 2] and [3]. The method developed in the previous works is extended to the study of a semi-infinite n-s multi-film structure. This structure is constructed as follows. First, we obtain a crystal thin film which may be either normal or superconducting by cutting a perfect infinite crystal at two separate paralled atomic planes. And then a mixed unit O composed of a thin film A and a thin film B is formed by close metallic contact. Finally, a semi-infinite multi-film structure is constructed by placing unit O's consecutively along the direction perpendicular to the interface. The corresponding single particle Green's functions for each step have been calculated. When film A and B belong to different normal metal, the results of the numerical calculation for both the single particle density of state and the energy band of such a structure have been given. When films A and B are made of the same normal metal, the results are equivelent to that of ref [7]. Futher-more, the equations for the case that one of the thin films is superconducting have been derived. The numerical results show that 1) the whole n-s multi-film structure is superconducting, and a finite peak appears in single particle density of states near the original gap edge, 2) the whole structure is gapless just as expect.