报告题目：Coupling Chirality, Polar Order, and Altermagnetic Spin Splitting in a Hybrid Manganese Chloride

报 告 人：Alessandro Stroppa

报告时间：2026年7月7日 19：30

报告地点：物理楼W105会议室

内容摘要：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.