强激光场、磁自旋分裂、磁电多铁材料、电荷向列序 | 本周物理讲座

1

报告人：王兵兵，中国科学院物理研究所

时间：7月7日（周二）10:00

单位：中国科学院理论物理研究所

地点：南楼6520

摘要:

阿秒脉冲的产生及自由电子激光技术的发展促使高频激光光源得到大力开发和应用。我们利用强场频域理论及含时演化方法研究高频激光场与原子分子相互作用的动力学过程，包括原子在强场中的重碰电离过程；利用分子在双色圆偏振光场中的电离谱探测其电子密度分布；以及原子在阿秒脉冲中双光子双电子电离过程等。

2

报告人：储昭强，哈尔滨工程大学，青岛创新发展基地

时间：7月7日（周二）15:00

单位：中国科学院物理研究所

地点：M楼249

摘要:

磁电耦合效应于19世纪50年代，首次被材料物理学家提出。与传统的单一铁性材料（铁磁、铁电、铁弹）相比，多铁性材料因具备磁-电耦合特性，为发展新型磁传感器、高效磁天线、低功耗存储器等功能器件提供了新思路，在磁探测、磁通信、磁定位等重要领域发挥着不可替代的作用。报告人长期围绕磁电功能器件开展研究，发展了磁电复合材料非线性动力学模型、提出了强耦合的磁电材料体系、研制了系列高灵敏磁电传感器和高效率低频机械天线。本报告主要介绍课题组在磁电谐振器非线性动力学理论、高效低频磁力谐振器设计、高性能磁收发天线研制及其在磁探测/磁通信/磁定位应用方面的研究进展。报告最后讨论多铁耦合材料和低频磁力谐振器在工程应用中尚存在的问题以及下一代微型化微功耗低频磁天线的研究方向。

报告人简介:

储昭强，哈尔滨工程大学教授/博导，北京大学理学博士，省优秀青年基金项目获得者。长期围绕压电/磁电器件设计和低频磁传感/磁通信技术开展研究。主持基金委青年项目和重点项目课题，主持科技部重点研发子课题（2项），主持军科委166，173重点项目子课题以及其他省部级纵向项目或横向课题十余项。截止目前在Nature Communications、Advanced Materials、Advanced Energy Materials、Advanced Functional Materials、Research、IEEE Transactions on Antennas and Propagation、Science Bulletin等国际高水平期刊上共发表 SCI论文60余篇，申请发明专利15项，登记软件著作权2项，合作出版专著2部，参与行业标准2项。担任期刊编委：Scientific Reports、客座编辑：Sensors, Crystals、青年编委：Journal of Advanced Dielectrics；担任国家自然科学基金委员会评议专家、山东省科技专家库专家、国网科技部专家库专家、全国磁性材料与器件专家委员会委员、中国仪表功能材料分会电子元器件关键材料与技术专委会委员；担任IEEE Transactions on Industrial Electronics, IEEE Transactions on Antennas and Propagation, Applied Physics Letters, APL materials等数十种期刊审稿人。

3

报告人：Alessandro Stroppa，CNR-SPIN Institute (Italy)

时间：7月7日（周二）19:30

单位：清华大学物理系

地点：物理楼W105会议室

摘要:

Hybrid manganese halides enable the coexistence of molecular chirality, polar order, and magnetic exchange within a single lattice. Here, we combine first-principles calculations with spin-space-group analysis to investigate the synthesized enantiomeric pair [(R)/(S)-MPA]2[MnCl4(H2O)] (MPA = beta-methylphenethylammonium). We predict that its compensated magnetic state hosts altermagnetic spin splitting in the nonrelativistic limit, and that the coupled chiral, polar, and magnetic degrees of freedom define a symmetry-related manifold. From this manifold, we derive simple sign rules for the electronic and magneto-optical response: reversing both chirality and polarity, or reversing the magnetic domain alone, inverts the spin splitting throughout the Brillouin zone, whereas reversing chirality alone or polarity alone changes the spin-splitting sign only in symmetry-selected regions. With spin-orbit coupling, reversing chirality or magnetic order flips the Kerr rotation angle, while changing the polar variant leaves it unchanged. These results reveal a chemically accessible route to translate molecular handedness into symmetry-controlled spin splitting and magneto-optical readout in hybrid manganese halides. Critically, we show that the sign and momentum pattern of the splitting are governed by the interplay of the chiral, polar, and magnetic degrees of freedom. This interplay opens the possibility to control the spin splitting through a judicious design of the organic cations, by modulating their chirality and polarity.

报告人简介:

Alessandro Stroppa is a Research Director of the CNR-SPIN Institute (Italy) and deputy director of the research unit in L’Aquila (Italy). He received his PhD in Theoretical Condensed Matter Physics from University of Trieste (Italy) in 2006, and he continued his research in computational materials science at University of Vienna in the group of Prof. Georg Kresse (VASP Team). After 2009, he joined the CNR in Italy where he became permanent staff in 2012. He is contract professor at University of L’Aquila (Italy), and invited professor at Shanghai and South East University (China). His current research areas deal with solid-state physics and material science. Specifically, he is interested in 3D and 2D hybrid inorganic-organic perovskites, non-magnetic and magnetic 2D systems with special focus on photo-ferroic, multiferroic, magnetoelectric, twistronic, topological, magneto-optical and nonlinear optical properties, skyrmions, etc. He has great experience with Density Functional Theory (DFT) methods for the study of the structural, electronic and magnetic properties using all-electrons as well as pseudopotential approaches implemented in numerical codes.

4

报告人：穆森, 马克斯·普朗克复杂系统物理研究所

时间：7月8日（周三）10:00

单位：中国科学院物理研究所

地点：M830

摘要:

Disordered systems often reveal their universal physics not only through averages, but through fluctuations. We will present two connected examples, from quantum localization to directed-polymer glass. First, we address a long-standing challenge in two-dimensional Anderson localization: characterizing fluctuations beyond the localization length. We show that these fluctuations can be understood through a mapping to directed polymers in random media, a paradigmatic model in the Kardar-Parisi-Zhang (KPZ) universality class. The second part focuses on finite-density directed polymers, a minimal model of glassy line matter. Direct simulation of this problem faces an “exponential wall” in the number of polymers, which we overcome by reformulating the problem as spectral filling. The key physics revealed here is that the absence of self-averaging in disordered systems can manifest as distinct critical exponents characterizing cumulants of thermodynamic observables. These works illustrate why fluctuations are central in statistical physics of disordered systems: they reveal universal laws and collective behaviours that are invisible at the level of average quantities alone. They also point toward a broader program of using fluctuation statistics to connect quantum localization and glassy physics.

报告人简介:

Sen Mu completed his undergraduate and doctoral studies in physics at the National University of Singapore (NUS). He is currently a postdoctoral researcher at the Max Planck Institute for the Physics of Complex Systems in Dresden, Germany. His recent research focuses on statistical and condensed matter physics of nonequilibrium phenomena in complex systems, including dynamics, localization, topology, criticality, and universal fluctuations in both classical and quantum disordered systems.

5

报告人：Atahualpa S. Kraemer，National Autonomous University of Mexico

时间：7月8日（周三）14:00

单位：中国科学院物理研究所

地点： D楼206会议室

摘要:

Quasicrystals have long challenged our understanding of structural order. In this presentation, we introduce a new approach that integrates the cut-and-project method with the generalized dual method to generate an entirely new class of quasiperiodic tilings. This technique reveals a novel local isomorphism class with a remarkable property: the ability to transition from a quasicrystalline system to a classical crystalline system through tile reconfiguration. This property can contribute to our understanding of how order emerges and helps bridge the gap between quasiperiodicity and periodic.

报告人简介:

Atahualpa S. Kraemer studied physics at the Faculty of Sciences of the National Autonomous University of Mexico (UNAM), where he also obtained his Ph.D. in Physics under the supervision of David P. Sanders, graduating in 2014. That same year he began his postdoc in Düsseldorf, Germany working in the group of Michael Schmiedeberg, a postdoc that continued in Erlangen, Germany until July 2016. In August 2016 he got a position as an associate professor at UNAM in the area of statistical physics where he currently works. His research areas are colloids, glasses, jammed systems, and quasicrystals. In 2022 he was promoted to full professor, and recently he was nominated for the award "National University Distinction Recognition for Young Academics in the area of Research in Exact Sciences 2023" at UNAM.

6

报告人：Changyoung Kim，Seoul National University

时间：7月9日（周四）10:00

单位：清华大学物理系

地点： 物理楼W105会议室

摘要:

Two-dimensional (2D) systems can exhibit physical properties that are markedly different from those of their three-dimensional (3D) counterparts, as reduced dimensionality can profoundly alter electronic behavior. Atomically thin materials further enable precise control and manipulation of physical properties. While many novel 2D systems are obtained by exfoliating van der Waals materials, an alternative and more conventional route is thin-film growth[1][2][3][4]. In this presentation, I will introduce our efforts to measure and control the electronic properties of one–unit-cell (UC)–thick films using epitaxial thin-film growth combined with in situ angle-resolved photoemission spectroscopy (ARPES). I will focus in particular on single-UC SrIrO₃ (SIO) films[5].A single-UC SIO film has the same crystal structure as a single layer of Sr₂IrO₄, a relativistic Mott insulator. Accordingly, single-UC SIO exhibits an electronic structure similar to that of Sr₂IrO₄, including a Mott-insulating state with short-range antiferromagnetic order. Remarkably, metallic states can be induced by epitaxial strain when SIO films are grown on substrates with different lattice constants. This strain-induced metallic state retains strong correlation effects and displays much sharper spectral features than those observed in Sr₂IrO₄, enabling detailed polarization-dependent ARPES measurements. Our polarization-dependent experiments [1] suggest that the ground state of single-UC SIO may host a charge nematic bond order. Preliminary STM results support the interpretation.

报告人简介:

Prof. Kim received his Ph.D. in Applied Physics from Stanford University. After working at SSRL as a staff member, he took a faculty position at Yonsei University in the department of Physics. He moved to Seoul National University as a professor in the department of Physics and Astronomy as well as an associate director of the center for correlated electron systems. His expertise is in angle resolved photoelectron spectroscopy on correlated materials, including high temperature superconductors and topological materials. His recent research interest is focused on investigation of novel electronic phases, via in-situ ARPES, that can be realized in atomically thin films of correlated materials. In addition to the atomically thin film results, his notable accomplishments include observation of spin-charge separation and discovery of the role of orbital angular momentum in solids.

封面图片来源：https://zhuanlan.zhihu.com/p/372297059

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