Transport, Dynamics, and High Tc

传输、动力学和高温

• 批准号: 8814311
• 负责人: Philip Allen
• 金额: $ 20.86万
• 依托单位: SUNY at Stony Brook
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-11-01 至 1992-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8814311&HistoricalAwards=false
• 关键词: Transport; Dynamics; Tc

The conduction of heat and electricity in condensed matter will be studied theoretically in four diverse situations. Two of these, diffusive electrical transport in highly disordered alloys, and heat transport in insulating glasses, will be assisted by large scale computer evaluations of "exact" Kubo formulas designed both to test simpler approximations and to elucidate mechanisms of transport. The alloy problem uses the conventional independent electron model, and the Kubo-Greenwood formula. The glass problem will use the analogous harmonic approximation, and the analog conductivity formula which has not been previously worked out. Among the aims of these projects are "saturation" of resistivity, and the occurrence in metals of negative temperature coefficients of resistivity. Also a rigorous test will be made of the KKR-CPA theory of alloy resistivity. The two other regimes involve quasi-particle transport, in conventional band Fermi liquid metals and in the new oxide superconductors. For the former, band theory will be used to extract coupling constants from the anistropic resistivity of hexagonal metals, and also to analyze the Hall coefficients. For the latter, an effort will be made to deduce the nature of the current carrying quasi-particles and of the scattering mechanisms, by comparison with experimental measurements.

我们将在四种不同的情况下从理论上研究凝聚态物质中的热传导和电传导。其中两个，高度无序合金中的扩散电传输，以及中空玻璃中的热传输，将得到大规模计算机评估的帮助，这些公式旨在测试更简单的近似，并阐明传输机制。合金问题采用传统的独立电子模型和久保-格林伍德公式。玻璃问题将使用类似的谐和近似，以及以前没有得到的类似的电导率公式。这些项目的目标之一是“饱和”电阻率，以及在金属中出现负的电阻率温度系数。此外，还将对KKR-CPA合金电阻率理论进行严格的测试。另外两个机制涉及准粒子输运，在传统的费米液态金属和新的氧化物超导体中。对于前者，将利用能带理论从六方金属的各向异性电阻率中提取耦合常数，并分析霍尔系数。对于后者，将努力通过与实验测量的比较来推断电流携带准粒子的性质和散射机制。