Stereoscopic Insight into Dilute Superconductivity of Perovskite Semiconductors

钙钛矿半导体稀超导性的立体洞察

• 批准号: 2225888
• 负责人: Jeremy Levy
• 金额: $ 50.95万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-12-01 至 2025-11-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2225888&HistoricalAwards=false
• 关键词: Stereoscopic; Insight; into; Dilute; Superconductivity

Non-technical AbstractUnderstanding the physical mechanism that gives rise to the phenomenon of superconductivity in some materials remains challenging, even decades after the first successful theory of superconductivity was developed by Bardeen, Cooper, and Schrieffer. Some semiconducting materials manage to become superconducting when doped with very few electrons, contradicting conventional theory. One such material, strontium titanate, a perovskite oxide, was shown to be a superconductor in 1964. More recently, superconductivity was discovered in a similar compound, potassium tantalate, whose properties are similar, but not identical, to strontium titanate. This research program compares the properties of nanometer-scale devices fabricated from potassium tantalate with devices made from strontium titanate as a way to understand the fundamental behavior, including the origin of superconductivity, of both systems. These devices are created using two complementary approaches: (1) conductive atomic force microscope lithography, and (2) ultra-low-voltage electron-beam lithography. Both techniques are capable of creating nanometer-scale devices whose properties reveal fundamental aspects of these materials and why they behave the way they do. The resulting insights are important for developing novel quantum technologies that make use of the remarkable properties of these materials. The project provides scientific research opportunities available to students at all levels, especially to traditionally underrepresented groups in STEM. Research opportunities will specifically be provided to students who are in their first or second year in college in the hope that some will continue throughout their undergraduate career and beyond. One of the most challenging aspects of scientific mentorship, especially to underrepresented groups, is how to instill a “growth” mindset. A “mindset intervention” method recently implemented in an upper-level course in introductory quantum mechanics will be adapted to undergraduate and PhD students working in a research environment. Its efficacy for instilling a growth mindset will be assessed. Technical AbstractThis research project investigates the microscopic origin of superconductivity in potassium tantalate (KTO). Nanoscale devices are created with KTO(110) and KTO(111) using techniques previously developed by the PI to control conductivity and superconductivity in strontium titantate (STO)-based heterostructures. The project directly addresses important questions such as: Why do KTO(111) and KTO(110) heterostructures exhibit superconductivity while KTO(100) does not? Is KTO superconductivity associated with a near-surface structural phase transition? Does KTO exhibit signatures of electron pairing outside of the superconducting regime (like STO)? What is the role of spin-orbit coupling? The “stereoscopic” insight provided by this research program focused on KTO, when combined with an existing base of recent knowledge about STO, will help to pinpoint which shared properties of KTO and STO conspire to produce superconducting behavior at exceptionally low densities. A deeper understanding of a, presumably, shared mechanism may lead to higher-temperature analogues, or simply help provide a deeper understanding of a family of materials that may one day be exploited for future quantum technologies.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.

非技术抽象理解产生某些材料中超导性现象的物理机制仍然受到挑战，即使是在Bardeen，Cooper和Schrieffer开发的第一个成功的超导性理论之后的几十年之后。一些半导体的材料在用很少的电子掺杂时就可以变得超导向，这与常规理论相矛盾。一种这样的材料，一种钛酸盐，一种钙钛矿氧化物，在1964年被证明是一种超导体。最近，在类似的化合物，tantalate钾钾的特性相似，但不相同的钛酸盐中发现了超导体。该研究计划比较了塔坦酸钾制造的纳米尺度设备与由钛酸标制造的设备，作为了解这两种系统的基本行为，包括超导性的起源。这些设备是使用两种完整的方法创建的：（1）导电原子力显微镜岩性摄影和（2）超低电压电子束岩性造影。两种技术都能够创建纳米尺度的设备，其属性揭示了这些材料的基本方面以及它们的行为方式。最终的见解对于开发新型量子技术很重要，这些技术利用这些材料的显着特性。该项目为学生提供了科学研究机会，尤其是STEM中传统代表性不足的群体。研究机会将为在大学第一年或第二年的学生提供专门提供，希望在整个本科生职业及以后继续进行一些研究机会。科学心态最挑战的方面之一，尤其是对代表性不足的群体，如何灌输“成长”心态。最近在高级课程入门量子力学中实施的一种“心态干预”方法将适用于在研究环境中工作的本科和博士生。它将评估其灌输增长心态的有效性。技术摘要研究项目研究了诱使钾（KTO）中超导性的显微镜起源。使用PI先前开发的技术来控制基于KTO的电导率和超导性，使用KTO（110）和KTO（111）创建纳米级设备（111）。该项目直接解决了重要的问题，例如：为什么KTO（111）和KTO（110）异质结构暴露了超导性，而KTO（100）则没有？ KTO超导性是否与近表面结构相变相关？ KTO在超导状态外（例如Sto）外是否表现出电子配对的特征？自旋轨道耦合的作用是什么？该研究计划提供的“立体”洞察力与KTO相结合时，将重点介绍有关STO的现有知识的基础，这将有助于查明在异常低密度下共享KTO和Sto Consipe的哪些共享特性，以产生超导行为。对某种（大概是共同的机制）的更深入的了解可能会导致更高的类似物，或者简单地帮助您深入了解一系列材料家族，这些材料可能有一天被探索，这些材料可能会用于未来的量子技术。这项奖项反映了NSF的法定任务，并通过使用该基金会的知识分子的智力和广泛的影响来评估NSF的法定任务，并被视为珍贵的支持。

项目成果

Mott‐Limited Thermopower of Pascal Electron Liquid Phases at the LaAlO3/SrTiO3 Interface

Mott-LaAlO3/SrTiO3 界面处帕斯卡电子液相的有限热电势

• DOI: 10.1002/pssb.202200612
• 发表时间: 2023
• 期刊: physica status solidi (b
• 作者: Jiang, Puqing;Tang, Yuhe;Lee, Hyungwoo;Lee, Jung-Woo;Eom, Kitae;Eom, Chang-Beom;Ban, Heng;Irvin, Patrick;Levy, Jeremy
• 通讯作者: Levy, Jeremy

Breaking electron pairs in the pseudogap regime of SmTiO3-SrTiO3-SmTiO3 quantum wells

SmTiO3-SrTiO3-SmTiO3 量子阱赝能隙区域中电子对的断裂

• DOI: 10.1103/physrevb.108.l201118
• 发表时间: 2023
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Wu, Xinyi;Chen, Lu;Li, Arthur;Briggeman, Megan;Marshall, Patrick B.;Stemmer, Susanne;Irvin, Patrick;Levy, Jeremy
• 通讯作者: Levy, Jeremy