Themperature Dependence of Chemical Potential and Tunneling Conductance of a Two-Dimensional van Hove singularity Model for High Temperature superconductor.
| Autor: | Nie-Chuan Chen, 陳乃權 |
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| Rok vydání: | 1994 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 82 In this thesis we try to use vHs model to explain some physical properties of high temperature superconductor. First we study the chemical potential difference between normal state and superconducting state. It shows that the difference can be as large as 1meV. Compared with Fermi energy, 1meV is small and we can neglect its influence on gap and Tc. Nevertheless we notice that 1meV can be experimentally observed. We find that the tendency of the result of this model is the same as that of experiment. Second we use a phenomenological method to study the tunneling conductance. We assume the tunneling probability is proportional to the group velocity of electron and add a rectifying term. The conductance will display double peaks and asymmetry. And then the double peaks broaden to a broader peak. Hense it is difficult to point out the real value of energy gap. This may be the reason why the value 2gap/KTc of many experiments are scattered and why it does not conform to traditional BCS result. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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