Numerical Study of Two-Dimensional t-J Model

• Main Authors: Shih, Chi-Tin, 施奇廷
• Other Authors: Lee Ting-Kuo, Wu Mao-Kuen
• Format: Others
• Language: en_US
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/67736320680995471957

博士 === 國立清華大學 === 物理學系 === 85 === To understand the physical properties and mechanism of the hightemperature superconductors, a strongly correlated electronicsystem, the two-dimensional $t-J$ model, is studied numerically.A new trial wave function with both antiferromagnetic andsuperconducting long-range order is derived from the mean-field theory.We develop a powerful numerical method, the power-Lanczos method,for studing the strongly correlated electron systems.We found that the dispersion relation of one hole in antiferromagnetcan be explained by the theory of d-RVB together with antiferromagnetism.As the number of doped holes increases, the antiferromagnetic long-range orderdecreases rapidly and vanishes for doping density $x sim 5%$.In the high density limit, phase separates into a hole- freeHeisenberg island and a hole-rich region at $J_c/t = 0.6 pm 0.1$.$J_c/t$ increases as the hole density increases. In the physicalregion of high temperature superconductors, the signal ofsuperconductivity of this model is too weak to explain the high$T_c$ of the high temperature superconductors.