Development of a New Approach to Contactless Transport Measurements at Cryogenic Temperatures

开发低温非接触式运输测量新方法

• 批准号: 0216880
• 负责人: Thomas Gramila
• 金额: $ 28.86万
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-15 至 2008-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0216880&HistoricalAwards=false
• 关键词: Development; New; Approach; Contactless; Transport

Advances both in the development of new materials and in fundamental understanding of new physics are often coupled to advances in experimental technology. This work extends such technology via an instrument permitting conventional transport style measurements to be made without the use of ohmic contacts. The approach is based on the use of capacitive coupling to samples. Such a system, while involving significant experimental challenges, offers considerable promise for the investigation of physical phenomena where conventional ohmic contacts can either not be used, or are unreliable to use. Examples of such areas of investigation include 2-D electron systems with extremely low electron densities, for which the relative importance of electron interaction are greatly enhanced, and low density samples at very high magnetic fields, where ohmic contacts can be notoriously difficult. Another area is the study of the metal insulator transition, where the combined effects of low densities, disorder, and magnetic field effects can combine to make ohmic contacts unreliable. These measurement capabilities will also benefit the investigation of new materials, since transport measurements can be used as a diagnostic tool without the considerable effort often necessary to develop ohmic contacts. The unique requirements of a capacitively-based measurement approach requires the development of new electronic and cryogenic techniques and instrumentation. Combined with the prospect for exploration of important topics in physics, its development will provide valuable training and experience for graduate students.Experience has demonstrated that pushing at extremes of temperature, magnetic field, or other measurement parameters, has exposed inadequacies in our knowledge of materials. Exploring such areas has often led to new and fundamental advances in our understanding of materials and their physics, and even to the development of new materials. This work will extend experimental capabilities by the creation of an instrument for making contact-less electrical measurements of electronic materials in cryogenic environments. The measurement system will provide experimental access to a number of areas, areas for which the difficulty of making conventional electrical contacts effectively prevents investigation. The instrument itself represents a technical challenge, involving low-noise measurements and complex sample environments, and its use will involve technologically important materials. It provides a valuable arena for the training of graduate students in both advanced technology and fundamental physics, whose training is a cornerstone of our technological infrastructure.

在新材料的开发和对新物理的基本理解方面的进步往往与实验技术的进步相结合。 这项工作扩展了这样的技术，通过仪器允许传统的运输方式的测量，而不使用欧姆接触。 该方法是基于使用电容耦合到样品。 这样的系统，而涉及重大的实验挑战，提供了相当大的承诺，为调查的物理现象，传统的欧姆接触不能使用，或不可靠的使用。 这样的调查领域的例子包括2-D电子系统与极低的电子密度，电子相互作用的相对重要性大大提高，和低密度样品在非常高的磁场，欧姆接触可能是出了名的困难。 另一个领域是金属绝缘体转变的研究，其中低密度、无序和磁场效应的组合效应可以联合收割机组合以使欧姆接触不可靠。这些测量能力也将有利于新材料的研究，因为输运测量可以用作诊断工具，而无需花费大量精力来开发欧姆接触。 基于电容的测量方法的独特要求需要开发新的电子和低温技术和仪器。 结合物理学重要课题探索的前景，它的发展将为研究生提供宝贵的训练和经验。经验表明，在温度、磁场或其他测量参数的极端情况下推动，暴露了我们对材料知识的不足。 探索这些领域往往会导致我们对材料及其物理学的理解取得新的根本性进展，甚至导致新材料的开发。 这项工作将通过创建一种用于在低温环境中对电子材料进行非接触式电气测量的仪器来扩展实验能力。 该测量系统将为一些领域提供实验性的访问，这些领域的传统电接触的困难有效地阻止了研究。 该仪器本身是一项技术挑战，涉及低噪声测量和复杂的样品环境，其使用将涉及技术上重要的材料。 它提供了一个宝贵的竞技场的研究生在先进技术和基础物理的培训，其培训是我们的技术基础设施的基石。