NSF/DMR-BSF: Quantum transport of charge and heat in correlated electron systems

NSF/DMR-BSF：相关电子系统中电荷和热量的量子传输

基本信息

批准号：
1742752
负责人：
Georg Schwiete
金额：
$ 31.5万
依托单位：
University of Alabama Tuscaloosa
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-05-01 至 2023-04-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1742752&HistoricalAwards=false
关键词：
NSF DMR BSF Quantum transport

项目摘要

NONTECHNICAL SUMMARYThe National Science Foundation and the United States -- Israel Binational Science Foundation (BSF) jointly support this collaboration between a US- and an Israel-based researcher. The NSF Division of Materials Research funds this award, which supports research and education on fundamental aspects of charge and heat transport in metallic systems. Measurements of electric currents that flow through a condensed matter system are often the tool of first resort for characterizing newly synthesized materials, or for gaininig deeper insights into the nature of interesting phases of matter. Often, measuring the flow of heat can provide valuable supplementary information, in particular in cases where quantum mechanical effects and interactions between the carriers are important. This is because heat currents can be driven even when electric charge carriers are immobile. While electric transport has been studied extensively in many systems, thermal or thermoelectric transport remains relatively poorly understood. To take full advantage of existing experimental techniques, it is therefore crucial to further improve our theoretical understanding of these transport processes. That is the main goal of this research project. In additional to its scientific merit, better knowledge of fundamental mechanisms of charge and heat transport, especially in semiconductors, holds promise for improving energy efficiency in electronic devices. Further impact of this activity will lie in training graduate students and postdoctoral fellows. Specifically, junior participants can greatly benefit from this international collaboration, which will allow them extended visits at a prestigious, non-US institute where they can be exposed to different ideas and approaches, and make connections that will help them in their future careers.TECHNICAL SUMMARYThe National Science Foundation and the United States -- Israel Binational Science Foundation (BSF) jointly support this collaboration between a US- and an Israel-based researcher. The NSF Division of Materials Research funds this award, which supports research and education on thermal and thermoelectric transport in correlated electron systems. In correlated electron systems, thermal and thermoelectric transport coefficients offer complementary information as they probe different aspects of the electron dynamics. To take full advantage of these experimental techniques, it is crucial to further improve our theoretical understanding of transport processes involving both electric charge and heat. Theoretical understanding of transport in complex materials is often impeded by multiple factors including strong correlations, impurities, Fermi-surface geometry, and phonons. It is therefore important to study systems where only some of these complications occur and can be studied in isolation to gain insights that may then be applied to more complex systems. Following this strategy, the research will initially focus on the disordered electron liquid near the metal-insulator transition, and then branch out to include more exotic strongly correlated systems.The main goals of the research project are: (i) To study theoretically the temperature dependence of the thermopower on the metallic side of the metal-insulator transition in disordered electron liquids. In particular, we will explore possible violations of the Mott-relation and the role of particle-hole asymmetry. (ii) To explore the effects of strong interactions on electric and thermal transport. In two-dimensional electron liquids, we intend to explore electric transport at the crossover between the low-temperature regime dominated by impurity scattering and higher temperatures where electron-electron collisions prevail. For strongly correlated materials, the project will focus on the response to a nonuniform temperature, where similar mechanisms can be at work.Deepening our knowledge on fundamental mechanisms of thermoelectric and thermal transport, especially in semiconductors, may improve energy efficiency in electronic devices. In particular, thermoelectric coolers and generators could benefit from understanding how material properties like disorder, interactions or the distance from a critical point affect transport coefficients. Further impact of this activity will lie in training graduate students and postdoctoral fellows. Specifically, junior participants can greatly benefit from this international collaboration, which will allow them extended visits at a prestigious, non-US institute where they can be exposed to different ideas and approaches, and make connections that will help them in their future careers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术摘要国家科学基金会和美国 - 以色列双性科学基金会（BSF）共同支持美国和以色列研究人员之间的这种合作。 NSF材料研究部研究基金该奖项，该奖项支持金属系统中电荷和热运输基本方面的研究和教育。流经凝结物质系统的电流的测量通常是表征新合成材料或更深入地深入了解物质阶段本质的首次度假胜地的工具。通常，测量热流可以提供有价值的补充信息，特别是在载体之间的量子机械效应和相互作用很重要的情况下。这是因为即使电荷载体不动，也可以驱动热电流。尽管在许多系统中对电动传输进行了广泛的研究，但热电传输或热电运输的理解仍然相对较差。为了充分利用现有的实验技术，因此对于进一步提高我们对这些运输过程的理论理解至关重要。这是该研究项目的主要目标。除了其科学优点外，对电荷和热传输的基本机制（尤其是在半导体中）的更好了解还有望提高电子设备的能源效率。这项活动的进一步影响将在于培训研究生和博士后研究员。具体而言，初级参与者可以从这项国际合作中受益匪浅，这将使他们在一个著名的非美国研究所进行扩展访问，在那里他们可以接触到不同的想法和方法，并建立联系，以帮助他们在未来的职业中有助于他们的职业。 NSF材料部研究基金该奖项基金，该奖项支持相关电子系统中的热电和热电运输研究和教育。在相关的电子系统中，热电传输系数在探测电子动力学不同方面时提供了互补信息。为了充分利用这些实验技术，至关重要的是要进一步提高我们对涉及电荷和热量的运输过程的理论理解。对复杂材料中传输的理论理解通常会受到多种因素，包括强相关性，杂质，费米 - 表面几何形状和声子。因此，重要的是研究仅发生其中一些并发症的系统，并且可以孤立地研究以获取可以应用于更复杂系统的见解。遵循此策略，该研究最初将集中在金属 - 绝缘体过渡附近的无序电子液体上，然后分支以包括更异国情调的强密切相关的系统。研究项目的主要目标是：（i）从理论上研究热培养基对金属 - 金属过渡器金属液体液体中金属量的温度依赖性。特别是，我们将探讨可能违反莫特相关的侵犯和粒子孔不对称的作用。（ii）探索强相互作用对电气和热传输的影响。在二维电子液体中，我们打算探索以杂质散射和较高温度为主的低温状态之间的跨界电动传输，而电子电子碰撞占了上风。对于密切相关的材料，该项目将集中于对非均匀温度的响应，在这种材料中可以使用相似的机制。简化我们对热电和热传输的基本机制的了解，尤其是在半导体中，可能会提高电子设备中的能源效率。特别是，热电冷却器和发电机可能会受益于了解诸如混乱，相互作用或距临界点距离之类的材料特性如何影响传输系数。这项活动的进一步影响将在于培训研究生和博士后研究员。具体而言，初级参与者可以从这项国际合作中受益匪浅，这将使他们在享有声望的非美国研究所进行扩展访问，在那里他们可以接触到不同的想法和方法，并建立联系，以帮助他们在未来的职业中有助于他们。该奖项反映了NSF的法定任务，反映了通过使用基金会的智力效果和广泛的评估来进行评估和广泛的评估。