Correlated electrons and novel temperature scales at the surfaces of 4f materials: Insights from ARPES

Denis Vyalykh 

Donostia International Physics Center, Spain

报告时间：2024年11月25日（周一）下午14:00

报告地点：紫金港校区段永平教学楼2号楼212报告厅

摘要：

For a long time, Rare-Earth (RE) intermetallic materials have attracted considerable interest because of their rich and exotic properties. A key point of the involved physics is the delicate interplay between itinerant electrons and the lattice of localized 4f states. Note here that the surfaces of such materials often do not receive as much attention as their bulk. We will focus on a class of RET₂Si₂ compounds, where T is transition metal atoms, which possess the ThCr₂Si₂ type structure. Besides their unique bulk properties, as we will see these materials reveal a rather unusual phenomena at the surface and can be considered as models for studying the peculiarities of 4f physics within the non-centrosymmetric Si-T-Si-RE surface-silicide blocks. Our results demonstrated quite nicely that the Si-T-Si-RE surfaces of the RET₂Si₂ materials serves as a versatile playground for studying the fundamental properties linked with f-d interactions at reduced dimensionality. It represents a kind of construction kit with Rashba spin-orbit coupling, Kondo interaction, crystal-electric fields and magnetic exchange with different strengths as building blocks. The obtained results make a call for detailed studies of the properties emerging at the surfaces and sub-surface areas of many strongly correlated Ce-, Eu-, and Yb-based materials with layered, quasi-2D structure.

报告人简介：

Denis Vyalikh is currently a IKERBASQUE research professor at Donostia International Physics Center (DIPC) at San Sebastian, Spain. He has worked in the field of condensed-matter physics over 25 years, using electron spectroscopic methods based on the application of synchrotron radiation. His research focuses on the quantum physics of electrons in strongly correlated materials, with a comprehensive characterization of bulk and surface properties and related temperature scales, particularly in lanthanide transition-metal compounds. His pioneering works on unveiling the fine electronic structures in Ce/Yb-Kondo lattices and mixed-valent compounds, as well as the discovery of a cubic Rashba effect, have been well-received in the research community. He has published 270 papers, with average citations per item of 30 and with an actual h-index of 48 (Scopus) and 57 (Google Scholar).