粲夸克、太赫兹、纳米结构阵列、电子自旋弛豫 | 本周物理讲座

摘要：

This presentation reports on the wafer-scale fabrication of metallic nanostructure arrays with highly ordered periodicity. With the semiconductor-based lithography and sputter deposition, various metallic arrays including metallic nanotube array (MeNTA), metal mesh (MM), and metallic pillar array (MPA) are fabricated. The MeNTA has been received the American Chemical Society (ACS) award at Japan Nano Tech 2018. The array structure is manufactured by sputtering metals onto a contact-hole array template created in the photoresist. We utilized both ferrous (stainless steel) and nonferrous alloys (Cu-, Ni-, Al-, and Ti-based), as well as elemental metals (Cu, Ag, and Au), to form these structures. The proposed arrays can be fabricated over a wide range of heights and diameters (from a few hundred nm to 20 µm) and in various shapes, including tall cylinders, dishes, and rhombuses. Furthermore, when combined with other nanomaterials (e.g., ZnO nanowires, graphene oxide, or Au nanoparticles), arrays become nanohybrids suitable for numerous applications. These applications include thermal emitters, triboelectric nanogenerators, SERS-active biosensors, and anti-icing devices.

报告人简介：

Professor Jinn P. Chu holds a Ph.D. in Materials Science from the University of Illinois at Urbana-Champaign (UIUC) and is currently a Chair Professor in the Department of Materials Science and Engineering at National Taiwan University. He has served as the Director of the Graduate Institute, the Director of the Nano Center, the Associate Dean of the College of Engineering, and the Vice President for Research and Development at the university. Additionally, he has held positions such as the President of the Taiwan Coating Association and the Vice President of the Materials Society. He has published over 220 academic papers in international journals, been granted 49 patents, and led multiple large-scale projects. Currently, he serves as the Associate Editor for the American Vacuum Society’s journal, JVST. In 2022 and 2023, he was recognized in the Stanford University Career Impact Ranking, listing him among the top 2% of scientists globally. He has received numerous awards, including the American Chemical Society Award, the Silver Medal at the Concours Lépine International Invention Exhibition in France, the Ministry of Science and Technology’s Outstanding Research Award, the Youxiang Technology Invention Award, the Hou Jindui Distinguished Honor Award, the Coating Association Excellence Contribution Award, the Materials Society Service Award, the National Innovation Award, the Taipei University of Technology Outstanding Alumni Award, the Outstanding Research Award from National Taiwan University of Science and Technology, and the Excellent Teacher Award from National Taiwan Ocean University.

报告人：徐俊卿，台湾科技大学

时间：10月22日（周二）10:00

单位：中国科学院物理所

地点：物理所M楼238

腾讯会议ID：813-899-946

摘要：

固体中的体相电子自旋非平衡过程，如自旋弛豫和退相位、自旋耗散、自旋光电响应等，是影响相应自旋电子器件性能的关键因素。这些过程的准确理论模拟，对于理解相关的物理机制、发现新型自旋电子学材料和优化器件工作条件等都至关重要。基于量子主方程方法，报告人等发展了一套适用性广泛的第一性原理方法以模拟自旋弛豫和退相位、自旋耗散和自旋光电流等过程。该方法包含了对电子-声子等散射过程的量子描述，并准确地描述了自旋轨道耦合、光电相互作用和外场的作用。因此，它能够模拟不同温度、掺杂水平和外场条件下的自旋非平衡过程。基于该方法，报告人等揭示了卤化钙钛矿、石墨烯等新型材料的自旋弛豫和退相位机制，预测了锗烯具有优异的自旋电子学性质，并提出了描述一类重要自旋电子学材料自旋弛豫的新物理参量。

报告人简介：

徐俊卿，现为合肥工业大学物理系教授。2016年于中国科学技术大学取得博士学位,随后在德国慕尼黑大学和美国加州大学圣克鲁兹分校从事博士后研究。获教育部和安徽省青年人才项目资助。目前主要从事自旋电子学、电子输运、二维材料电子结构等方面的理论研究。研究成果发表在Phys. Rev. Lett.，Nat. Commun.，Nano Lett.等学术刊物上。

报告人：何沛伦，上海交通大学

时间：10月23日（周三）10:30

单位：中国科学院理论物理所

地点：北楼202

报告人：Haim Diamant，Tel Aviv University

时间：10月23日（周三）15:00

单位：中国科学院物理所

地点：M楼255会议室

报告人：Congjun Wu，Westlake University

时间：10月23日（周三）15:00

单位：北京大学物理学院

地点：西563会议室

摘要：

Typical mean-field theories for many-body states rely on two-fermion orderings. Order parameters lie in either the particle-particle channel such as pairing orders for superconductivity, or, in the particle-hole channel such as spin-density-wave orders for antiferromagnetism. Nevertheless, in high energy quantum chromodynamics, three quarks form a colorless baryon, and in nuclear physics, two protons and two neutrons form a spin and isospin singlet a-particle. We examine this class of multi-particle fermion multi-particle clustering instabilities in one-dimensional spin-3/2 fermion systems via the renormalization group and bosonization method, which exhibit the quartetting superfluidity (charge 4e) and quartet density wave orderings. For a two-band superconductivity, we identify a normal state with a two-particle-two-hole type ordering exhibiting time-reversal symmetry breaking because of strong phase fluctuations.We also introduce a mechanism of the charge-6e state via fustration of pair-density-wave state，which may be relevant to the recent hc/6e oscilations observed in the little-parks type experiments in kagome superconductors

报告人简介：

Congjun Wu received his Ph.D. in physics from Stanford University in 2005 and did his postdoctoral research at the Kavli Institute for Theoretical Physics, University of California, Santa Barbara, from 2005 to 2007. He became an Assistant Professor in the Department of Physics at the University of California, San Diego in 2007, an Associate Professor in 2011, and a professor in 2017. In 2021, he became a Chair Professor at Department of Physics, Westlake University and the founding chair of this department. He was selected as a New Cornerstone Investigator (the inaugural award) in 2023, elected to a Fellow of American Physical Society in 2018, and awarded the Sloan Research fellowship in 2008. His research interests are exploring new states of matter and reveling their organizing principles, including quantum magnetism, superconductivity, topological states, mathematical physics, and the numerical method of quantum Monte Carlo simulations.

摘要：

Novel spintronic devices can play a role in the quest for GreenIT if they are stable and can transport and manipulate spin with low power. Devices have been proposed, where switching by energy-efficient approaches is used to manipulate topological spin structures.

We combine ultimate stability of topological states due to chiral interactions with ultra-efficient manipulation using novel spin torques. In particular orbital torques increase the switching efficiency by more than a factor 10.

We use skyrmion dynamics for non-conventional stochastic computing applications, where we developed skyrmion reshuffler devices based on skyrmion diffusion, which also reveals the origin of skyrmion pinning. Such diffusion can furthermore be used for Token-based Brownian Computing and Reservoir Computing.

We go beyond simple ferromagnets and study multilayers with antiferromagnetic coupling termed synthetic antiferromagnets. We find that the diffusion dynamics is drastically enhanced due to the topology and efficient dynamics can be induced by spin torques. Finally, we find novel topological spin structures, such as bi-merons that are stabilized in synthetic antiferromagnets.

报告人简介：

Mathias Kläui is professor of physics at Johannes Gutenberg-University Mainz and adjunct professor at the Norwegian University of Science and Technology.

He received his PhD at the University of Cambridge, after which he joined the IBM Research Labs in Zürich. He was a junior group leader at the University of Konstanz and then became associate professor in a joint appointment between the EPFL and the PSI in Switzerland before moving to Mainz. His research focuses on nanomagnetism and spin dynamics on the nanoscale in new materials. His research covers from blue sky fundamental science to applied projects with major industrial partners. He has published more than 400 articles and given more than 250 invited talks. He is a Fellow of the IEEE, IOP and APS and has been awarded a number of prizes and scholarships. He has been one of the 2020/2021 IEEE Magnetics Society Distinguished Lecturers.