报告题目：Moiré engineering and novel electronic transport at oxide interfaces

主讲人：曾长淦教授 中国科学技术大学教授

报告时间：2022年6月23日16：00-18：00

报告地点：物理楼B座304会议室

主办单位：光伏材料省重点实验室 拓扑功能材料研究中心

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报告摘要：

Moiré engineering has recently emerged as an effective approach to control quantum phenomena in condensed matter systems. Here we demonstrate electronic moiré patterns in films of a prototypical magnetoresistive oxide, La0.67Sr0.33MnO3, epitaxially grown on LaAlO3 substrates. Microscopic moiré profiles of both the electronic conductivity and ferromagnetism are observed, which can be attributed to the coexistence and interaction of two distinct incommensurate patterns of strain modulation. Our work provides a potential route to achieving spatially patterned electronic textures on demand in strained epitaxial materials [1].

On the other hand, the states inside superconducting gaps in tunneling spectra have been revealed to be associated with a spectrum of nontrivial effects, such as Majorana bound states. Here we further present our recent progresses in the tunneling measurements involving oxide heterostructures, and the central findings include: 1) Zero-bias conductance peaks effectively tuned by gating-controlled Rashba spin-orbit coupling in the hybrid junctions composed of the conducting LaAlO3/SrTiO3 interface and superconducting Nb [2]; 2) In-gap Andreev bound states observed for the hybrid junctions involving the newly discovered superconducting LaAlO3/KTaO3 interface, which can be attributed to spin-triplet pairing [3]. These discoveries collectively have implications in various research fronts from superconducting spintronics to topological superconductivity.

References:

[1] Chen et al., Nat. Phys. 16, 631 (2020)

[2] Guo et al., Phys. Rev. Lett. 126, 057701 (2021)

[3] Unpublished

个人简介：

曾长淦，中国科学技术大学教授，博士生导师，教育部“长江学者”特聘教授，教育部“新世纪优秀人才支持计划”入选者。主要围绕多自由度耦合的新型低维电子体系，通过多尺度实验手段，在实现高质量材料精控制备、探索特殊电子结构和拓扑量子物性关联、发展新型物性调控手段等方面开展了一系列研究工作。共发表学术论文近百篇, 包括1篇Nature，5篇Nature子刊， 14篇PRL。承担过多项国家级重要科研任务，包括中科院战略先导专项项目、国家自然科学基金委重点项目、科技部重大研究计划子课题等。