DMREF: Collaborative Research: Materials design of correlated metals as novel transparent conductors

非技术描述：透明导体是影响社会的许多技术的关键组成部分，包括太阳能电池、触摸屏、平板显示器、发光二极管和激光器。事实证明，寻找在可见光谱中兼具高导电性和优异光学透明度的材料具有挑战性：金属通常是良导体，但会反射而不是透射可见光，而玻璃等绝缘体高度透明，但不携带电流。该项目的目标是追求项目团队成员在之前的工作中开发的非常规范例，以发现和开发基于地球丰富元素的新型透明导电材料，这些材料表现出明显更好的性能，并且可以比长期行业标准氧化铟锡 (ITO) 更低的成本制造。将材料性能测量和计算数据库的挖掘与候选材料的结构和性能的预测模拟相结合的理论分析将与实验室合成、表征和优化真实材料的工作紧密结合。在“材料基因组计划”的背景下，协调全国范围内的努力，加速先进材料的发现、开发和部署，项目过程中开发的用于将理论和实验整合到材料设计中的工具和技术将提供给社区，以推动更广泛的材料设计挑战取得进展。透明导体开发的突破将推动能源发电、照明和被动式建筑设计的绿色技术。技术描述：将透明性和高导电性这两个矛盾特性结合起来的传统范例是大量掺杂宽带隙？因此透明？半导体以增加其导电性。新范例的想法不是使透明半导体更具导电性，而是使金属光学透明。这可以通过相关效应增加电子有效质量来实现，在带间跃迁高于可见光范围的目标系统中，相关效应会降低可见光范围内的金属反射率。发现新型透明导体的设计空间涵盖了广泛的家族，包括相关氧化物、层状硫族化物、磷族化合物和金属间化合物。将采用分层三级搜索方法。首先，将使用易于应用的限定标准在可用的材料设计空间中预先筛选候选材料，然后在密度泛函理论 (DFT) 水平上对晶体结构、电子能带以及与光学和电学传输特性相关的量进行高通量第一原理计算。在第三级，将在密度泛函平均场理论（DMFT）中研究相关效应，以完善较低级的搜索标准并确定最有前途的系统以进行进一步研究。在实验室中，这些候选材料的电传输和光学特性的合成和表征以及与理论预测的比较将有助于完善设计原理和扩展可用于技术应用的透明导电材料组。

NON-TECHNICAL DESCRIPTION: Transparent conductors are a critical component in many technologies affecting society, including solar cells, touch screens, flat panel displays, light emitting diodes and lasers. Finding materials that combine high electrical conductivity with excellent optical transparency in the visible spectrum has proved challenging: metals typically are good conductors but reflect rather than transmit visible light, while insulators like glass are highly transparent but do not carry an electrical current. The goal of this project is to pursue an unconventional paradigm, developed in previous work by members of the project team, to discover and develop new transparent conducting materials based on earth-abundant elements that exhibit substantially better performance and can be made with lower cost than the long-standing industry-standard indium-tin-oxide (ITO). Theoretical analysis combining mining of databases of materials property measurements and computations with predictive simulations of the structure and properties of candidate materials will be closely integrated with efforts in the laboratory to synthesize, characterize and optimize real materials. In the context of the Materials Genome Initiative coordinating efforts across the nation to accelerate the discovery, development and deployment of advanced materials, tools and techniques for integration of theory and experiment in materials design that are developed in the course of the project will be made available to the community to advance progress in broader materials design challenges. Breakthroughs in the development of transparent conductors will advance green technologies for energy generation, lighting, and passive building designs.TECHNICAL DESCRIPTION: The conventional paradigm to combine the contradicted properties of transparency and high electrical conductivity is to heavily dope a wide band gap ? thus transparent ? semiconductor to increase its electrical conductivity. Rather than making a transparent semiconductor more conductive, the idea of the new paradigm is to make a metal optically transparent. This can be done by increasing the electron effective mass by correlation effects, which reduces the metal reflectivity in the visible range, in targeted systems for which interband transitions are above the visible range. The design space for the discovery of new transparent conductors spans a wide range of families, including correlated oxides, layered chalcogenides, pnictides, and intermetallic compounds. A hierarchical three-level search approach will be pursued. First, material candidates will be pre-screened in the available materials design space using simple-to-apply qualifier criteria, followed by high-throughput first-principles computations of crystal structure, electronic bands, and quantities related to optical and electrical transport properties at the level of density functional theory (DFT). At the third level, correlation effects will be studied within density functional mean field theory (DMFT) to refine the lower level search criteria and identify the most promising systems for further investigation. In the laboratory, synthesis and characterization of the electrical transport and optical properties of these candidate materials and comparison with theoretical predictions will aid in the refinement of design principles and the expansion of the set of transparent conducting materials available for technological applications.