強激光場、磁自旋分裂、磁電多鐵材料、電荷向列序 | 本周物理講座

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報告人：王兵兵，中國科學院物理研究所

時間：7月7日（周二）10:00

單位：中國科學院理論物理研究所

地點：南樓6520

摘要:

阿秒脈沖的產生及自由電子激光技術的發展促使高頻激光光源得到大力開發和應用。我們利用強場頻域理論及含時演化方法研究高頻激光場與原子分子相互作用的動力學過程，包括原子在強場中的重碰電離過程；利用分子在雙色圓偏振光場中的電離譜探測其電子密度分布；以及原子在阿秒脈沖中雙光子雙電子電離過程等。

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報告人：儲昭強，哈爾濱工程大學，青島創新發展基地

時間：7月7日（周二）15:00

單位：中國科學院物理研究所

地點：M樓249

摘要:

磁電耦合效應于19世紀50年代，首次被材料物理學家提出。與傳統的單一鐵性材料（鐵磁、鐵電、鐵彈）相比，多鐵性材料因具備磁-電耦合特性，為發展新型磁傳感器、高效磁天線、低功耗存儲器等功能器件提供了新思路，在磁探測、磁通信、磁定位等重要領域發揮著不可替代的作用。報告人長期圍繞磁電功能器件開展研究，發展了磁電復合材料非線性動力學模型、提出了強耦合的磁電材料體系、研制了系列高靈敏磁電傳感器和高效率低頻機械天線。本報告主要介紹課題組在磁電諧振器非線性動力學理論、高效低頻磁力諧振器設計、高性能磁收發天線研制及其在磁探測/磁通信/磁定位應用方面的研究進展。報告最后討論多鐵耦合材料和低頻磁力諧振器在工程應用中尚存在的問題以及下一代微型化微功耗低頻磁天線的研究方向。

報告人簡介:

儲昭強，哈爾濱工程大學教授/博導，北京大學理學博士，省優秀青年基金項目獲得者。長期圍繞壓電/磁電器件設計和低頻磁傳感/磁通信技術開展研究。主持基金委青年項目和重點項目課題，主持科技部重點研發子課題（2項），主持軍科委166，173重點項目子課題以及其他省部級縱向項目或橫向課題十余項。截止目前在Nature Communications、Advanced Materials、Advanced Energy Materials、Advanced Functional Materials、Research、IEEE Transactions on Antennas and Propagation、Science Bulletin等國際高水平期刊上共發表 SCI論文60余篇，申請發明專利15項，登記軟件著作權2項，合作出版專著2部，參與行業標準2項。擔任期刊編委：Scientific Reports、客座編輯：Sensors, Crystals、青年編委：Journal of Advanced Dielectrics；擔任國家自然科學基金委員會評議專家、山東省科技專家庫專家、國網科技部專家庫專家、全國磁性材料與器件專家委員會委員、中國儀表功能材料分會電子元器件關鍵材料與技術專委會委員；擔任IEEE Transactions on Industrial Electronics, IEEE Transactions on Antennas and Propagation, Applied Physics Letters, APL materials等數十種期刊審稿人。

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

時間：7月7日（周二）19:30

單位：清華大學物理系

地點：物理樓W105會議室

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.

報告人簡介:

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.

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報告人：穆森, 馬克斯·普朗克復雜系統物理研究所

時間：7月8日（周三）10:00

單位：中國科學院物理研究所

地點：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.

報告人簡介:

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.

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

時間：7月8日（周三）14:00

單位：中國科學院物理研究所

地點： D樓206會議室

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.

報告人簡介:

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.

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報告人：Changyoung Kim，Seoul National University

時間：7月9日（周四）10:00

單位：清華大學物理系

地點： 物理樓W105會議室

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 SrIrO? (SIO) films[5].A single-UC SIO film has the same crystal structure as a single layer of Sr?IrO?, a relativistic Mott insulator. Accordingly, single-UC SIO exhibits an electronic structure similar to that of Sr?IrO?, 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 Sr?IrO?, 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.

報告人簡介:

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.

封面圖片來源：https://zhuanlan.zhihu.com/p/372297059

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