Metals, Insulators, and Superconductors

金属、绝缘体和超导体

• 批准号: 9118414
• 负责人: Philip Allen
• 金额: $ 24万
• 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: 1991
• 资助国家: 美国
• 起止时间: 1991-11-01 至 1995-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9118414&HistoricalAwards=false
• 关键词: Metals; Insulators; Superconductors

Theory will be developed for the electronic and vibrational properties of metals, insulators and superconductors, especially crystalline oxides such as copper-and bismuth-oxide superconductors and vanadium-oxide based metal-insulator systems. The underlying motive is to explore the still obscure mechanism for high temperature superconductivity. A secondary motive for the research is to improve understanding of the diverse and poorly understood electrical transport properties of these materials. As a model system barium-bismuth-oxide will be studied in detail. The charge carriers in this insulator are bipolarons. A continuous evolution through an exotic superconducting state to a normal metallic conductor occurs as bismuth is replaced by lead. Polaron and bipolaron models will be developed and tested to model resistivity, Hall coefficient, and superconductivity. Other model systems to be studied are niobium-oxide and vanadium-dioxide. The latter has a metal-insulator transition at a temperature convenient for device applications such as memory elements. The effect of lattice distortion and phonons on the transition will be studied. Thermal conduction will also be studied in a model of amorphous silicon.

将开发金属、绝缘体和超导体的电子和振动特性的理论，特别是晶体氧化物，如铜和氧化铋超导体以及基于氧化钒的金属绝缘体系统。 其根本动机是探索仍然模糊的高温超导机制。 这项研究的第二个动机是提高对这些材料的多样化和知之甚少的电传输特性的理解。 作为模型系统，将详细研究氧化钡铋。 该绝缘体中的电荷载流子是双极子。 当铋被铅取代时，就会发生从奇异超导状态到正常金属导体的持续演化。 将开发和测试极化子和双极化子模型，以模拟电阻率、霍尔系数和超导性。 其他要研究的模型系统是氧化铌和二氧化钒。 后者在适合存储元件等器件应用的温度下具有金属-绝缘体转变。 将研究晶格畸变和声子对跃迁的影响。 还将在非晶硅模型中研究热传导。