实陈数拓扑材料、超导二极管、阻挫磁体、超导薄膜、高熵超高温陶瓷 | 本周物理讲座

1

报告人：胜献雷，北京航空航天大学

时间：5月20日（周二）14:00

单位：中国科学院物理研究所

地点：物理所M楼631

腾讯会议ID：795-238-455

摘要：

高阶拓扑绝缘体是近几年提出的一类新奇拓扑物态。我们计算预测已经在实验上合成的石墨炔是一个二维二阶拓扑绝缘体材料，构建了第二类Stiefel-Whitney数（实陈数）与二阶拓扑绝缘体之间的联系，提出了一类磁性二维二阶拓扑绝缘体的普适构建方案，并预言Bi/EuO结构是磁性二维二阶拓扑绝缘体。拓展到三维，预测三维石墨二炔是三维二阶实陈数节线半金属，三维石墨一炔则是三维二阶实陈数拓扑绝缘体。在非线性霍尔效应领域，提出外尔半金属可增强本征非线性平面霍尔效应。通过模型研究，我们发现增强效应主要源于轨道贡献，基于第一性原理计算，在材料CuTlSe2中计算了这些特性。

报告人简介：

胜献雷，北京航空航天大学物理学院，教授，博导。2011年博士毕业于中国科学院大学，先后在美国加州州立大学、中国科学院物理研究所、美国特拉华大学和新加坡科技设计大学做博士后或访问学者。2015年入职北航物理学院，长期从事计算凝聚态物理研究，尤其是材料拓扑物性、磁性与输运性质的计算研究，在PRL，NatureComm，PRB等期刊发表SCI论文60余篇。

2

报告人：杨帆，天津大学

时间：5月20日（周二）15:00

单位：中国科学院物理研究所

地点：物理所M楼631

腾讯会议ID：795-238-455

摘要：

TiSe2 is a typical transition-metal dichalcogenide known for its charge-density wave order. In this study, we report the observation of an unusual anisotropic negative magnetoresistance in exfoliated TiSe2 nanoflakes at low temperatures. Unlike the negative magnetoresistance reported in most other transition-metal dichalcogenides, our results cannot be explained by either the conventional two-dimensional weak localization effect or the Kondo effect. A comprehensive analysis of the data suggests that the observed anisotropic negative magnetoresistance in TiSe2 flakes is most likely caused by the three-dimensional weak localization effect. Our findings offer valuable information for understanding the phase-coherent transport processes in TiSe2.

报告人简介：

杨帆，2007年本科毕业于南京大学物理系，2012年于中科院物理所获得博士学位，2012-2018年先后在大阪大学和科隆大学从事博士后研究，2018年至今在天津大学物理系量子交叉研究中心工作，任北洋英才计划长聘副教授、研究员。杨帆的主要研究方向为量子输运和微纳米量子器件，共发表论文20余篇，被引用2000余次。

3

报告人：S.R.Kulkarni，加州理工学院光学天文台

时间：5月20日（周二）15:30

单位：北京大学物理学院

地点：KIAA-auditorium

摘要：

Following the Big Bang the Universe was homogeneous in matter, energy and barren of chemistry. It is the stars which, through their life and death, built up the periodic table. Astronomers have now identified several classes of cosmic explosions of which supernovae constitute the largest group. The Palomar Transient Factory was an innovative 2-telescope, and its successor, the Zwicky Transient Factory (ZTF), is a high tech project with gigantic CCD cameras and sophisticated software system, and squarely aimed to systematically find "blips and booms in the middle of the night".

The speaker will talk about the great returns and surprises from this project: super-luminous supernovae, new classes of transients, new light on progenitors of supernovae, detection of gamma-ray bursts by purely optical techniques, routine identifications of planets being engulfed by their aging parent stars and troves of pulsating stars and binary stars. ZTF is poised to become the stepping stone for the national flagship project, the Rubin Observatory.

报告人简介：

S. R. Kulkarni is the George Ellery Hale Professor of Astronomy at the California Institute of Technology. He served as Executive Officer for Astronomy (1997-2000) and Director of Caltech Optical Observatories for the period 2006-2018. He was recognized by Cornell University with an AD White Professor-at-Large appointment. Kulkarni received an honorary doctorate from the Radboud University of Nijmegen, The Netherlands. He is the Chair of the Physical Sciences panel of the Infosys Science Foundation. Kulkarni obtained his undergraduate degree from the Indian Institute of Technology, Delhi and his PhD from UC Berkeley. He served a brief period as a postdoc at UC Berkeley and Caltech before joining the faculty rank at Caltech in 1987. Prof. Kulkarni's primary interests are the study of compact objects (neutron stars and gamma-ray bursts) and cosmic explosions. He is keenly interested in developing or refining astronomical methodologies. His awards include NSF's Alan T. Waterman Prize of the NSF, a fellowship from the David and Lucile Packard Foundation, a Presidential Young Investigator award from the NSF, the Helen B. Warner award of the American Astronomical Society, the Janksy Prize of Associated Universities, Inc, the Dan David Prize and the Shaw Prize. Kulkarni is a fellow or member of the following learned societies: the American Academy of Arts & Sciences, the Royal Society of London, the US National Academy of Sciences, Indian Academy of Sciences and the Royal Netherlands Academy of Arts and Sciences (KNAW).

4

报告人：Masao Doi，Nagoya University

时间：5月20日（周二）16:00

单位：中国科学院理论物理研究所

地点： 北楼202

5

报告人：江云峰，东南大学

时间：5月21日（周三）14:00

单位：中国科学院理论物理研究所

地点：北楼322

摘要：
Integrability is interesting, often associated with remarkable phenomena such as the existence of infinitely many conserved charges, factorized scattering and exact solvability. On the other hand, it is probably even more interesting to break integrability, giving rise to new phenomena such as particle production, resonance states, and notably, soliton confinements. In this talk, I will first review confinement in Ising field theory and the theoretical works to determine the associated meson spectrum. I will then present recent work in which we explore analogous phenomena in an Ising ladder system. In this setting, we observe similar confinement mechanisms but encounter a richer meson spectrum, including both interchain and intrachain mesons. I will discuss the methods used to determine these spectra and present the key findings of our study.

6

报告人：高尚，中国科学技术大学

时间：5月21日（周三）15:00

单位：北京大学物理学院

地点：物理楼，西563会议室

7

报告人：褚衍辉，华南理工大学

时间：5月22日（周四）10:00

单位：中国科学院物理研究所

地点：物理所M楼253

腾讯会议ID：993-486-049

摘要：

高熵陶瓷因具有巨大的组分空间，独特的微观结构以及可调控的性能近年来受到国内外研究学者的广泛关注，我们在国际上较早地开展了高熵超高温陶瓷材料研究，开发出系列高熵超高温陶瓷材料，建立了精准的相形成能力判据以及可迁移的机器学习势函数，实现了对其力-热性能的精准预测；发明了多种合成高熵超高温陶瓷粉体的方法，制备出系列高品质粉体，实现了公斤级批量化生产；揭示了高熵超高温陶瓷晶格畸变与力-热-电-磁性能之间的关联机理，开发出高韧、高强、高隔热、宽吸波高熵陶瓷材料；阐明了高熵陶瓷多组元协同抗氧化机制，开发出耐3600℃抗氧化高熵碳化物陶瓷材料。

报告人简介：

褚衍辉，华南理工大学研究员、博士生导师，2016年博士毕业于西北工业大学，其中2014年1月至2015年9月在美国哈佛大学博士联合培养。2017年开始从事高熵陶瓷材料研究工作，以第一或通讯作者在Nat Commun、Matter、Adv Mater、Adv Funct Mater、Acta Mater等期刊发表SCI论文100余篇，获授权国家发明专利30余件，主持基金委优青、科技部重点研发计划青年科学家等项目，曾获美国陶瓷学会Ross Coffin Purdy奖、教育部自然科学奖一等奖等，兼任中国硅酸盐学会测试技术分会副秘书长、《Journal of Materiomics》和《Int. J. Appl. Ceram. Technol.》期刊编委等。

8

报告人：Yakov Fominov，L.D. Landau Institute of Theoretical Physics, Russian Academy of Sciences

时间：5月22日（周四）15:00

单位：中国科学院理论物理研究所

地点：Lecture Hall on the 5th Floor of CCAST

Zoom Meeting ID: 825 1553 1170

Passcode: 654432

摘要：

In this talk, I will discuss the rapidly developing field of nonreciprocal effects in superconducting transport, also known as the superconducting diode effect. The essence of this phenomenon lies in the asymmetry of a system's properties when a supercurrent tlows in opposite directions. Such an effect requires the simultaneous breaking of tme-reversal and inversion symmetries. The underlying physical mechanisms can vary significantly, including effects of magnetic (and, more specifically, exchange) fields, spin-orbit interactions, and geometric asymmetry of the system. These effects can lead to nonreciprocacharge transport both in systems homogeneous along the current direction and in Josephson junctions.

9

报告人：杨明，香港理工大学

时间：5月22日（周四）15:00

单位：北京大学物理学院

地 点：物理大楼中212报告厅

摘要：

Two-dimensional (2D) semiconductors such as monolayer MoS₂ hold significant promise for advancing nanoelectronics. However, integrating high-k dielectrics with 2D semiconductors to achieve high performance devices remains a challenge. In this talk, I will present our understanding of designing high-performance interfaces between high-k dielectrics and 2D MoS2. First, we demonstrate that hydrogenation is an effective method for passivating dangling bonds at the interface between conventional high-k dielectrics and MoS₂, in which hydrogenation selectively occurs on high-k dielectrics such as Si3N4 and HfO2 without affecting the MoS2. Second, we introduce a data-driven approach to expedite the discovery of inorganic molecular crystals (IMCs) as high-k dielectrics. From enormous candidates in Materials Project, we identify 9 IMCs as the promising high-k dielectrics for 2D semiconductors. These findings advance the understanding of integrating high-k dielectrics with 2D semiconductors and could be useful for the development of a wide range of 2D electronic and optoelectronic devices.

报告人简介：

Dr. Ming Yang is currently an Assistant Professor in the Department of Applied Physics at The Hong Kong Polytechnic University (PolyU). He earned his Ph.D. from the National University of Singapore (NUS), where he also conducted postdoctoral research. Following this, Dr. Yang served as a Scientist at the Institute of Materials Research and Engineering in Singapore. Dr. Yang’s research focuses on accelerating the development of functional materials for advanced applications through high-throughput screening techniques, large-scale density functional theory (DFT) calculations, and machine learning. To date, Dr. Yang has authored or co-authored over 200 peer-reviewed articles in renowned journals, contributed to two book chapters, and filed three patents.

10

报告人：王明聪，大湾区大学（筹）

时间：5月23日（周五）10:00

单位：中国科学院物理研究所

地点：怀柔园区MA楼505会议室

腾讯会议：754-849-575

会议密码：2025

摘要：

YBCO超导薄膜的电学性能一致性与表面粗糙度和厚度均匀性的控制高度相关。然而，传统接触式等表征手段难以满足量产工艺对在线监测的高通量、无损化需求。本报告聚焦光学多模态无损表征技术，解析如何通过宽场干涉显微术实现纳米级粗糙度的快速全场映射，以及如何通过X射线反射/荧光光谱完成薄膜厚度的大面积扫描快速扫描，为PLD/MOCVD工艺研发人员提供及时和无损的质量评估手段，为工艺窗口的优化提供数据支撑。

报告人简介：

王明聪，四川大学学士和硕士、中国工程物理研究院博士、阿卜杜拉国王科技大学博士后研究员，现任大湾区大学（筹）特聘研究员、助理教授，主要从事超快激光光谱技术（瞬态吸收、太赫兹光谱、时间分辨光致发光光谱）及其在拓扑、超导、光伏和发光材料中的应用研究，在PRL、Nat.Commum.、Angew.Chem.等期刊发表多篇唯一第一作者学术论文，入选教育部海外青年人才、苏州汾彩领军人才、东莞市特色人才，兼任松山湖材料实验室客座研究员、东莞市微纳光场调控与感知重点实验室副主任。

11

报告人：João Maia，Peking University

时间：5月23日（周五）10:30

单位：中国科学院理论物理所

地 点：北楼322

摘要：

The long-range Ising model extends the classical Ising framework by allowing every pair of spins to interact, with interaction strength decaying polynomially in the distance between them. In one dimension, this system—often referred to as the Dyson model—exhibits spontaneous magnetization at sufficiently low temperature, a phenomenon absent in its nearest-neighbour counterpart. Another variation of the Ising model, called the random field Ising model (RFIM), incorporates an independent Gaussian random external field acting on each site. This model has garnered significant interest recently, and it is most notorious for its lack of a phase transition in two dimensions.

In this talk, I will present recent results on the existence and nature of phase transitions in the long-range RFIM. I will describe the techniques used to establish these findings and outline open problems and potential avenues for future research.

报告人简介：

João Maia is a postdoctoral researcher at Peking University under the supervision of Jian Ding. He earned his Ph.D. from the University of São Paulo, working under the supervision of Rodrigo Bissacot. His research focuses on classical statistical mechanics, with particular emphasis on long-range models and systems subject to external perturbations.

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