Microscopic Theory of Optical Excitations in Interface-Dominated Material Systems


This project deals with the microscopic modelling of electron-hole-pair excitations in interface dominated semiconductor materials. We plan to analyze the optically linear and nonlinear response and the formation dynamics of spatially inhomogeneous excitons (type-II or charge-transfer excitons) where the constituting electrons and holes are located in neighbouring material regions that are separated by an internal interface.

As model systems, we will focus (i) on semiconductor heterostructures with type-II band alignment and (ii) van-der Waals bonded heterostructures consisting of quasi-two-dimensional layers of transition-metal dichalcogenides (TMDC). We will concentrate on the properties of the interface specific charge-transfer (CT) excitations and plan to investigate the build-up of interface specific correlations as well as the CT exciton formation dynamics after optical excitation, the related excitonic nonlinearities, as well as the terahertz (THz) response of the optically excited semiconductor systems. In the TMDCs, we will extend our fully relativistic treatment of their excitonic properties and the interface specific modifications in heterostructure arrangements.

Project-related publications

  1. L. Meckbach, T. Stroucken, S.W. Koch
    Influence of the effective layer thickness on the groundstate and excitonic properties of transition-metal dichalcogenide systems
    Phys. Rev. B 97, 035425 (2018).
  2. C.E. Stevens, T. Stroucken, A.V. Stier, J. Paul, H. Zhang, P. Dey, S.A. Crooker, S.W. Koch, D. Karaiskai
    Superradiant Coupling Effects in Transition-Metal Dichalcogenides
    Optica 5, 749 (2018).
  3. L. Meckbach, J. Hader, U. Huttner, J. Neuhaus, J.T. Steiner, T. Stroucken, J.V. Moloney, S.W. Koch
    Ultrafast band-gap renormalization and build-up of optical gain in monolayer MoTe2
    Phys. Rev. B 101, 075401 (2020).
  4. I. Kilen, M. Kolesik, J. Hader, J.V. Moloney, U. Huttner, M.K. Hagen, S.W. Koch
    Propagation induced dephasing in semiconductor high-harmonic generation
    Phys. Rev. Lett. 125, 083901 (2020).
  5. M. Borsch, C.P. Schmid, L. Weigl, S. Schlauderer, N. Hofmann, C. Lange, J.T. Steiner, S.W. Koch, R. Huber, M. Kira
    Super-resolution lightwave tomography of electronic bands in quantum materials
    Science 370, 1204 (2020).

Prof. Dr. Stephan W KOCH

Principal InvestigatorPhilipps-Universität MarburgDepartment of PhysicsPhone: +49 6421 28-21336Project B4 (SW Koch)Project B7 (Stolz/SW Koch)Biography

Dr. Hanno Steiner, Researcher
Dr. Tineke Stroucken (m. Warncke), Researcher

Former Contributors
Dr. Christian Berger
Dr. Ulrich Huttner
Prof. Dr. Mackillo Kira
Dr. Mathias Per Ljungberg
Dr. Lars Meckbach
Dr. Osmo Vänskä