TMC21: Imaging topological states in photoelectron spectroscopy скачать в хорошем качестве

TMC21: Imaging topological states in photoelectron spectroscopy

Topological Matter Conference (TMC) 2021: Imaging topological states in photoelectron spectroscopy: from magnetic topological insulators to Weyl semimetals Hendrik Bentmann (Universität Würzburg) Over the past decade, topological states of matter have attracted wide interest in condensed matter physics and material science. In this talk, I will report on recent studies, based on angleresolved photoelectron spectroscopy (ARPES), of two types of topological materials: intrinsic magnetic topological insulators (IMTI) and Weyl semimetals (WSM). MTI are materials that combine a topological electronic band structure and magnetic order. The recently discovered van der Waals systems MnBi2Te4(Bi2Te3)n are the first compounds to realize this phenomenology intrinsically. I will present ARPES experiments for the n = 1 and 2 members of this material family, while crystalline and magnetic properties of the same samples will be discussed by Anna Isaeva (same session). Our experiments confirm the existence of topological surface states and show how their properties vary with surface termination. Furthermore, I will briefly describe our present efforts to realize these materials in two dimensions via molecular beam epitaxy. Weyl nodes are topologically protected intersections between non-degenerate electron bands and constitute the defining feature of WSM. At these special points in momentum space the Bloch wave functions show a special behavior: in the bulk the Weyl nodes constitute monopoles of Berry flux and at the surface their projections define the termination points of Fermi-arc surface states. I will discuss how these intricate electronic properties manifest in real materials and how they can be addressed experimentally by use of dichroism in ARPES. --------------------------------------------------- The Topological Matter Conference (TMC) focuses on recent developments in fundamental and applied aspects of broad classes of topological quantum systems and the synergy between them. Topics include topological insulators and Weyl semimetals, topological phononics and photonics, skyrmions, quantum metrology and more. The TMC is a joint effort between the H2020 FET-PROACTIVE projects TOCHA (GA: 824140) and SKYTOP (GA: 824123) with the objective to establish synergies and to mobilize the Topological Matter community. Intended to lead to an annual gathering, the first TMC will be celebrated in 2021 from June 28th to July 2nd. If the pandemic situation allows it, the conference will be hosted at the Eden Roc hotel in Sant Feliu de Guixols, Spain, including Plenary, Invited, Oral and Poster contributions. Otherwise, the conference will be virtual, likely with no poster presentations. For more information: https://topologicalmatter.org/program/