SFB 1170


    24.01.2020, 10:30 am

    Prof. Stefan Tautz - Forschungszentrum Jülich
    Brainstorming Session in HS P

    Title: The Role of Spectroscopy in the Realization of Topological Quantum Computing

    17.01.2020, 10:15 am

    Federico Cilento Elettra - Sincrotrone Trieste S.C.p.A. Italy
    i-RTG Lecture in HS P

    Title: Table-top time-resolved spectroscopies for complex materials


    Time-resolved spectroscopies have emerged as fundamental spectroscopic tools for probing complex materials, to both investigate ground-state-related properties and trigger phase transitions among different states with peculiar electronic and lattice structures. In recent years, they have been used to shed light on a large variety of open issues on the physics of complex and strongly-correlated materials. In particular, time-domain measurements have been widely used to disentangle, by their different timescales, the degrees of freedom of a system that at equilibrium are intertwined, thus advancing the comprehension of ground state properties of solid state compounds. Moreover, photoexcitation at high enough fluence makes it possible to trigger phase transitions among different states of a sample, often not attainable under equilibrium conditions, allowing to achieve a true ultrafast control over the functional properties of materials.

    Here I will report on a number of science cases where the non-equilibrium approach allowed to advance the comprehension of the materials properties, and show the latest science-driven advancements in the fields of time-resolved optical and photoelectron spectroscopies from table-top ultrafast light sources. Finally, I will discuss how table-top spectroscopies can complement experiments at large-scale facilities, including Synchrotron Radiation Sources and Free Electron Lasers.

    10.01.2020, 10:15 am

    Prof. Dr. Wulf Wulfhekel - Physikalisches Institut, KIT, Karlsruhe
    i-RTG Lecture in HS P

    Title: Design principles, challenges and techniques for scanning tunneling microscopy at mK temperatures


    Scanning tunneling microscopy (STM) and spectroscopy (STS) at temperatures in the mK regime requires special efforts. These include restricted design rules for cryostats capable to reach these temperatures in combination with low vibrations and long standing times. Often, the designs lead to machines that are difficult to handle. We will discuss, how to circumvent some of the pitfalls of common designs. To reach the necessary quality of electric signals and the thermalization of the electron temperature, special care has to be taken for many of the signal lines. We will introduce some of the techniques based on a 30mK design at KIT and will show, what trade-offs have to be taken and how the signal quality influences the measuring protocols at ultra-low temperatures.

    13.12.2019, 10:15 am

    Dr. Georg Rohringer - University of Hamburg
    i-RTG Lecture in HS P

    Title: Two-particle self-consistency and conservation laws in strongly correlated electron systems.


    In the lecture, I will discuss in detail the two-particle self-consistency relations and the conservation
    laws for the basic model for strongly correlated electron systems, i.e., the Hubbard model. More
    specifically, I will present I derivation of the equations of motion which connects the full two-particle
    vertex function with the self-energy. Then I will show, how the requirement of charge conservation
    leads to a constraint for the one-particle self-energy and the two-particle irreducible vertex. The final
    part of the lecture will address the question how in general approximate theories can be constructed
    which fulfill either the equation of motion and the Pauli principle[1] or the conservations laws[2].


    [1] G. Rohringer et al., Rev. Mod. Phys. 90, 025003 (2018).
    [2] G. Baym and Leo P. Kadanoff, Phys. Rev. 124, 287 (1961).



    06.12.2019, 10:15 am

    Prof. Dr. Carsten Timm - TU Dresden
    i-RTG Lecture in HS P

    Title: Group-theoretical analysis and synthesis of Hamiltonians


    The purpose of this lecture is to show how group theory can be used to analyze model Hamiltonians and also to construct such Hamiltonians based on symmetries. It should help to answer questions such as the following: Why did the authors of paper X write down this weird Hamiltonian? Is the model used in paper Y generic for systems of the relevant symmetry or does it contain hidden approximations? How can I construct a model Hamiltonian for some complicated lattice? Which symmetries of superconducting states are possible for a certain system?

    Lecture Notes

    29.11.2019, 10:15 am

    Prof. Dr. Claude Monney - University Of Fribourg
    i-RTG Lecture in SE7

    Title: Lecture on RIXS


    This lecture will be devoted to the basics of resonant inelastic x-ray scattering (RIXS). RIXS is a powerful and versatile modern x-ray spectroscopy. We will derive together the Kramers-Heisenberg formula describing RIXS using second-order perturbation theory. We will then discuss how a RIXS experiment is planned in practice, taking advantage of the absorption edge of relevant ions in materials to be chemically sensitive and of the scattering geometry to enhance its selectivity.

    In the last 10 years, the development of the RIXS technique and its application to correlated materials followed a steady and impressive progress. We will therefore illustrate the lecture with examples from the recent scientific literature and discuss them in details. For that purpose, we will show how RIXS can measure crystal field excitations, magnetic excitations or interband electron-hole excitations.

    18.10.2019, 10:15 am

    Prof. Dr. Herbert Pfnür - Leibniz Universität Hannover
    i-RTG Lecture in SE7

    Title: Elastic and inelastic scattering of low energy electrons

    Abstract: Due to their strong interaction with condensed matter, low energy electrons (1 to 500 eV) impinging on a solid surface can only penetrate very few layers before they are elastically or inelastically scat­tered. This fact not only generates high surface sensitivity, but also makes these electrons a very versatile tool for investigating both surface structure and low-energy excitations predominantly at surfaces. In this lecture I will give an overview about the various possibilities, starting with elastic, coherent electron diffraction. While long range order can mostly be dealt with in single scattering approxima­tion, short range (multiple) scattering contains all the information about the local structure, so that diffracted intensities as a function of energy and/or angle can be used to determine atomic positions at surfaces. Inelastic scattering generates characteristic excitations such as local vibra­tions of adsorbates, phonons, plasmons or electron-hole pairs. The discrimination between the various possibilities is sometimes not easy and requires the assistance of quantitative simulations. I will both discuss a few characteristic examples as well as experimental aspects.


    12.07.2019, 10:15 am

    Prof. Dr. CHristoph Tegenkamp - Technische Universität Chemnitz
    i-RTG Lecture in SE7

    Title: Electronic transport on surface structures: advantages, limitations and challenges


    14.06.2019, 14:15 pm

    Dr. Christian Tusche - Forschungszentrum Jülich, Peter Grünberg Institut (PGI-6)
    i-RTG Lecture in SE7

    Title: Principles and Applications of Spin-resolved Photoelectron Spectroscopy with the Momentum Microscope


    29.03.2019, 11:30 am

    Dr. Flavio de Souza Nogueira, IFW Dresden
    i-RTG Lecture in SE5

    Title: Chiral anomaly and second-quantized Berry phases


    27.03.2019, 01:00 pm

    Dr. Flavio de Souza Nogueira, IFW Dresden
    i-RTG Lecture in SE5

    Title: Haldane's topological nonlinear sigma model theory  of one-dimensional antiferromagnets


    26.03.2019, 01:00 pm

    Dr. Flavio de Souza Nogueira, IFW Dresden
    i-RTG Lecture in SE5

    Title: Nonlinear sigma models and topological action


    18.01.2019, 10:15 am

    Prof. Markus Donath, Universität Münster
    i-RTG Lecture in SE2

    Title: Putting a new spin on unoccupied electronic states


    17.01.2019, 02:00 pm

    Prof. Su Ning, EPFL, Lausanne, Switzerland
    i-RTG Lecture in SE5

    Title: Numerical conformal bootstrap II


    16.01.2019, 04:00 pm

    Prof. Su Ning, EPFL, Lausanne, Switzerland
    i-RTG Lecture in SE5

    Title: Numerical conformal bootstrap I


    15.01.2019, 04:00 pm

    Prof. Su Ning, EPFL, Lausanne, Switzerland
    i-RTG Lecture in SE5

    Title: Crash course in conformal field theory.


    30.11.2018, 10:15 am

    Thomasz Story, Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
    i-RTG Lecture in SE2

    Title: Thermoelectricity and topological materials

    18.06.2018, 10:15 am

    Dr. Moritz Hoesch, DESY, Hamburg,
    i-RTG Lecture in SE2

    Title: Momentum-resolved solid state spectroscopy using synchrotron radiation (IXS, ARPES)

    15.06.2018, 10:15 am

    Dr. Giancarlo Panaccione, ELETTRA synchrotron, Trieste, Italy
    i-RTG Lecture in SE2

    Title: From surface to bulk sensitivity via Photoelectron Spectroscopy with Synchrotron Radiation.

    01.12.2017, 10:15 am

    Anna Isaeva, TU Dresden
    i-RTG Lecture in SE2

    Title:Growth of bulk inorganic crystals: theory, tips and cheats

    21.07.2017, 10:15 am

    Gianni Profeta, l’Aquila, Italien
    i-RTG Lecture in SE2

    Title: Towards room temperature superconductivity

    12.05.2017, 10:15 am

    Dr. Silvia Picozzi, CNR-SPIN Chieti, Italien
    i-RTG Lecture in SE2

    Title: Interplay between spin and dipolar degrees of freedom

    01.07.2016, 10:00 am

    Prof. Dr. Markus Morgenstern, RWTH Aachen
    i-RTG Lecture in SE2

    Title: What we can learn about TIs from STM measurements

    22.04.2016, 10:00 am

    Prof. L. H. Tjeng, Max-Planck-Institute for Chemistry and Physics of Solids, Dresden
    i-RTG Lecture in SE2

    Title: Strongly correlated systems and their excitations: a back-of-the-envelope introduction

    29.01.2016, 10:00 am

    Eugene Krasovskii, Universidad del Pais Vasco
    i-RTG Lecture in SE2

    Title: Relativistic band structure and theory of angle- and spin-resolved photoemission