Materials World Network: Properties of Electrostatically Doped Oxide Superconductors

材料世界网：静电掺杂氧化物超导体的特性

• 批准号: 1209578
• 负责人: Allen Goldman
• 金额: $ 48万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1209578&HistoricalAwards=false
• 关键词: Materials; World; Network; Properties; Electrostatically

TECHNICAL SUMMARY:This Materials World Network project will synthesize, characterize and study experimentally, properties of high temperature superconductors such as the cuprates, whose carrier concentrations will be electrostatic altered in field effect transistor geometries employing an electronic double layer transistor (EDLT) technique that uses ionic liquids as gate dielectrics. In effect electrostatic doping would replace chemical doping. Since carrier concentration is a control parameter that governs the properties of these systems, this approach will facilitate the investigation of systems through continuous and reversible changes of carrier concentration. The program includes studies of X-ray scattering and superfluid density to supplement the usual measurements of electrical transport and magneto-transport. Electronic double layer transistors contain a gate electrode, a layer into which charge can be accumulated or depleted, source and drain electrodes, as well as electrodes for measuring longitudinal and transverse voltages. Ionic liquids are molten salts consisting of large ions such that their Coulomb interaction is sufficiently small to make them room temperature liquids. Upon applying a gate voltage, ions move to the surface of the layer to be doped, forming an electric double layer such that with the charge induced, acts as a capacitor of nanoscale thickness. The charge accumulation or depletion layers formed using EDLTs may be the order of just a few unit cells in thickness and will contain high electric fields and electric field gradients. The doped layer may be a two-dimensional rather than a three-dimensional superconductor. It is thus not a given that electrostatic doping is completely equivalent to chemical doping to the same charge level. On the other hand, when the microscopic process of electric field doping becomes well understood, considerable insight into the rich physics of the cuprates may be gained. NON-TECHNICAL SUMMARYThis Materials World Network project will employ ionic liquid field effect transistor configurations to electrostatically alter charge carrier densities, and study the resultant changes in the physical properties of high temperature superconductors. The usual approach to this is to prepare samples with different chemical compositions. This new approach eliminates the need to do this, speeding the rate of exploration. Ionic liquids, which are molten salts at room temperature, replace the gate insulator in the field effect transistor configuration. Their use can facilitate charge transfers more than 100 times greater than achievable with conventional insulators, because of the formation of an electronic double layer, which is in effect a capacitor with a nanometer scale gap. The broader impacts of the proposed program include training of graduate students in a traditional physics Ph.D. program and providing a venue for useful and positive research experiences for undergraduates from both Minnesota and elsewhere. In addition, this international effort will allow for strong interaction of personnel from the US and Spain, which will broaden the experience of young scientists in the global scientific community. Finally, the work described in this proposal may have an impact on the search for new superconductors, which is one of the grand challenges of contemporary condensed matter and materials physics. It could demonstrate that electrostatic doping is a viable alternative to traditional chemical doping in this quest. This project is supported by the Condensed Matter Physics program and the Office of Special Programs, Division of Materials Research.

技术摘要：该材料世界网络项目将在实验中综合，表征和研究高温超导体（例如丘比特）的特性，库酸酯的载体浓度将在现场效应的晶体效应晶体管几何形状中改变使用电子双层晶体管（EDLT）技术，该技术使用离子液体作为栅极液体作为栅极液体Decelectrics。实际上，静电掺杂将取代化学掺杂。 由于载体浓度是控制这些系统特性的控制参数，因此该方法将通过载体浓度的持续和可逆变化来促进系统的研究。 该程序包括对X射线散射和超流体密度的研究，以补充电气传输和磁通电场的通常测量。 电子双层晶体管包含一个栅极电极，该层可以累积或耗尽电荷，源和排水电极，以及用于测量纵向和横向电压的电极。离子液体是由大离子组成的熔融盐，因此它们的库仑相互作用足够小，可以使它们成为室温液体。施加栅极电压后，离子移动到层的表面进行掺杂，形成了电层，以使带电荷诱导，充当纳米级厚度的电容器。使用EDLT形成的电荷积累或耗尽层可能仅为厚度的几个单位单元，并且将包含高电场和电场梯度。 掺杂层可能是二维而不是三维超导体。 因此，没有给定静电掺杂完全等于化学掺杂到相同的电荷水平。 另一方面，当电场掺杂的显微镜过程得到充分了解时，可以获得对铜质丰富物理学的相当深刻的见解。非技术摘要材料世界网络项目将采用离子液体效应晶体管构型来改变电荷载体密度，并研究高温超导体物理特性的结果变化。通常的方法是准备具有不同化学成分的样品。 这种新方法消除了这样做的需要，从而加快了探索速度。离子液体在室温下是熔融盐，代替了田间隔热晶体管构型中的栅极绝缘体。由于形成电子双层，它们的使用可以促进电荷传输比常规绝缘子可实现的100倍以上，这实际上是具有纳米尺度间隙的电容器。 拟议计划的更广泛影响包括在传统物理学博士学位上对研究生进行培训。计划并为明尼苏达州和其他地方的本科生提供有用和积极的研究经验的场所。此外，这项国际努力将允许美国和西班牙的人员进行牢固的互动，这将扩大全球科学界的年轻科学家的经验。 最后，本提案中描述的工作可能会影响寻找新的超导体，这是当代冷凝物质和材料物理学的巨大挑战之一。 它可以证明静电掺杂是在此任务中传统化学掺杂的可行替代品。 该项目得到了凝结的物理计划和材料研究部特殊计划办公室的支持。