德国马尔堡大学 Prof. Ulrich Hoefer 6月17日上午学术报告

发布时间:2019-06-10访问量:186设置

Presenter: Prof.Ulrich HoeferDepartment of Physics, Philipps-University of Marburg, Germany

Topic: Band Structure Movies of Electrical Surface Currents

Time: 10:00AM, June.17th (Monday)

Location: Conference Room B, BLDG 909-1F


Abstract

Time-resolved photoelectron spectroscopy combines femtosecond pump-probe techniques with angle-resolved photoelectron spectroscopy (ARPES). I will show how this method can be used to perform measurements of electron transport at surfaces and interfaces in a contact-free fashion and with femtosecond time-resolution [1-3]. As the main example, I will discuss Dirac surface states of topological insulators. We induce electrical currents in these states with strong THz transients and directly access their dynamics in momentum space with subcycle time resolution. As a result of spin-momentum locking, the accelerated spin-polarized electrons reach ballistic mean free paths of several hundreds of nanometers. Our results show that topological insulators are promising materials for future lightwave-driven electronics operating at THz clock rates [3].

    

[1] J. Güdde, M. Rohleder, T. Meier, S. W. Koch, and U. H?fer, Science 318, 1287 (2007).

[2] K. Kuroda, J. Reimann, J. Güdde, and U. H?fer, Phys. Rev. Lett. 116, 076801 (2016).

[3] J. Reimann, S. Schlauderer, C. P. Schmid, F. Langer, S. Baierl, K. A. Kokh, O. E. Tereshchenko, A. Kimura, C. Lange, J. Güdde, U. H?fer, and R. Huber, Nature 562, 396 (2018).



Contact: Prof. Steffen Duhm


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