Polaronic effects in the Density Functional Theory for Superconductors

超导体密度泛函理论中的极化子效应

• 批准号: 61928804
• 负责人: Professor Dr. Eberhard K. U. Gross
• 金额: --
• 依托单位: Max-Planck-Institut für Mikrostrukturphysik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/61928804?language=en
• 关键词: Polaronic; effects; Density; Functional; Theory

Density functional theory of superconductivity has been rather successful in predicting material-specific properties, such as the critical temperature Tc, of conventional (BCS-type) superconductors. For the high-Tc cuprates, however, the presently available approximations of the xc free-energy functional fail to give the correct description. The goal of the proposed research is to construct and implement improved approximations of the xc functional by taking polaronic contributions into account. This is achieved by employing diagrammatic techniques of many-body perturbation theory. A dressed (polaronic) Greensfunction is obtained from solving a Dyson equation with a GW-type self-energy. This Greensfunction is then used as basic element in the diagrammatic construction of the xc free-energy functional. This construction is to be viewed as a first step towards a first-principles description of high-T−c superconductors.

超导性的密度泛函理论在预测材料特定的性质方面已经相当成功，例如传统（BCS型）超导体的临界温度Tc。然而，对于高Tc铜酸盐，目前可用的xc自由能泛函的近似值未能给出正确的描述。建议的研究的目标是构建和实施改进的xc泛函的近似考虑极化贡献。这是通过采用多体微扰理论的图解技术来实现的。通过求解具有GW型自能的Dyson方程，得到了一个缀饰（极化）格林函数.然后将此格林函数用作xc自由能泛函的图解构造中的基本元素。这种构造被视为迈向高T −c超导体第一性原理描述的第一步。