Matthias Sitte Curriculum Vitae

Transcription

1 Matthias Sitte Curriculum Vitae Johannes Gutenberg-Universität Mainz Institut für Physik Staudingerweg Mainz Germany +49 (0) msitte@uni-mainz.de ¹ +49 (0) r Personal information Name: Matthias Sitte Profession: Physicist, postdoctoral researcher Date of birth: December 3rd, 1982 Place of birth: Olpe, Germany Nationality: German Marital status: Married, two children Scientific interests Topics: Magnetic systems, magnetization dynamics, topological insulators, quantum phase transitions, low-dimensional quantum systems, strongly correlated matter Methods: Numerical simulations, tight-binding models, phenomenology, quantum field theory, renormalization group methods Experience Vocational Johannes Gutenberg-Universität Mainz Postdoctoral researcher, INSPIRE group of Prof. Dr. Jairo Sinova Mainz, Germany Nov 2015 Present Childcare related part-time employment: 50% Nov Dec 2015, 75% Jan Oct The University of Texas at Austin Postdoctoral researcher, group of Prof. Dr. Allan H. MacDonald University of Cologne Postdoctoral researcher, group of Prof. Dr. Achim Rosch Austin, TX, USA Jul 2013 Oct 2015 Oct 2012 Jun 2013 Paternity leave: Sep Dec University of Cologne Ph.D. student, group of Prof. Dr. Achim Rosch Jul 2008 Oct 2012 University of Cologne Diploma student, group of Prof. Dr. Achim Rosch Jul 2007 Jul 2008 Awards and fellowships Postdoctoral fellowship Deutscher Akademischer Austausch Dienst (DAAD) Jul 2013 Jun /6

2 Best Poster Prize WE-Heraeus-Seminar on Spin-orbit-driven transverse transport phenomena Dec 2012 Scholarship Bonn-Cologne Graduate School of Physics and Astronomy Apr 2007 Jun 2011 Scholarship Studienstiftung des deutschen Volkes Nov 2003 Jul 2008 Invited talks Hard Condensed Matter Seminars New York, NY, USA New York University Sep 2015 Title: Tight-Binding Approach towards an Effective Model for InAs/GaSb Quantum Wells Spintronics: Progress in Theory, Materials, and Devices Santa Barbara, CA, USA Kavli Institute for Theoretical Physics Dec 2013 Title: InAs/GaSb quantum wells as 2D TIs? Complex Quantum Systems Seminar Austin, TX, USA The University of Texas at Austin Oct 2013 Title: Interaction effects on almost flat surface bands in topological insulators Group Seminar (Prof. Dr. Wilhelm Zwerger Munich, Germany Technische Universitä München Jun 2013 Title: Interaction effects on almost flat surface bands in topological insulators Condensed Matter Seminar Austin, TX, USA The University of Texas at Austin Dec 2011 Title: Quantum Hall Effect in Topological Insulators Condensed Matter Theory Seminar New Brunswick, NJ, USA Rutgers University Oct 2009 Title: Emergent Lorentz Symmetry with Vanishing Velocity in a Critical Two-Subband Quantum Wire Group Seminar (Prof. Dr. Hans Kroha) Bonn, Germany Bonn University Apr 2009 Title: Emergent Lorentz Symmetry with Vanishing Velocity in a Critical Two-Subband Quantum Wire Conferences and workshops (selected) DPG Spring Meeting 2016 Regensburg, Germany Organizer of Spin Hall Effect and Spin-Orbit Torques tutorial, talk Mar 2016 APS March Meeting 2015 San Antonio, TX, USA Talk Mar 2015 APS March Meeting 2014 Denver, CO, USA Talk Mar 2014 Newspin3: spin phenomena from model systems to complex matter Mainz, Germany Poster presentation Apr 2013 DPG Spring Meeting 2013 Regensburg, Germany Talk Mar 2013 DPG Spring Meeting 2012 Berlin, Germany Talk Mar 2012 Newspin2: spin physics and topological effects in cold... College Station, TX, USA Poster presentation Dec /6

3 Workshop on Topological Insulators Langeoog, Germany organized by the SFB TR 12 Nov 2011 Tokyo-Cologne Workshop on Strongly Corr. Transition-Metal Comp. Sep 2011 DPG Spring Meeting 2011 Dresden, Germany Poster presentation Mar 2011 DPG Spring Meeting 2010 Regensburg, Germany Poster presentation Mar 2010 Newspin: spin manipulation in cold atoms and condensed... Utrecht, The Netherlands Poster presentation Jan 2010 Teaching Computer Physics with PD Dr. Ralf Bulla Tutor Summer 2012 Theoretical Physics II with PD Dr. Rochus Klesse Tutor Winter 2011 Quantum Physics with Prof. Dr. Achim Rosch Tutor Summer 2011 Solid State Theory with Prof. Dr. Achim Rosch Assistant Winter 2010 Computer Physics with Prof. Dr. Johannes Berg Tutor Summer 2010 Theoretical Physics II with Prof. Dr. Alexander Altland Tutor Winter 2009 Theoretical Physics I with PD Dr. Rochus Klesse Tutor Summer 2009 Mathematical Methods with Prof. Dr. Andreas Schadschneider Tutor Winter 2007 Winter 2008 Electrodynamics with Prof. Dr. Matthias Vojta Tutor Summer 2007 Quantum Physics with Prof. Dr. Achim Rosch Tutor Winter 2006 Linear Algebra I & II with Prof. Dr. Gudlaugur Thorbergsson Tutor Winter 2004 Summer 2005 Publications [1] M. Sitte, A. Rosch, J. S. Meyer, K. A. Matveev, and M. Garst: Emergent Lorentz Symmetry with Vanishing Velocity in a Critical Two-Subband Quantum Wire. Phys. Rev. Lett. 102, (2009). [2] M. Sitte, A. Rosch, E. Altman, and L. Fritz: Topological Insulators in Magnetic Fields: Quantum Hall Effect and Edge Channels with a Nonquantized θ Term. Phys. Rev. Lett. 108, (2012). 3/6

4 [3] M. Sitte, A. Rosch, and L. Fritz: Interaction effects on almost flat surface bands in topological insulators. Phys. Rev. B 88, (2013). [4] K. Everschor-Sitte and M. Sitte: Real-space Berry phases: Skyrmion soccer. J. Appl. Phys. 115, (2014), featured article. [5] K. Everschor-Sitte, M. Sitte, and A. H. MacDonald: Half-metallic magnetism and the search for better spin valves. J. Appl. Phys. 116, (2014). [6] K. Everschor-Sitte, M. Sitte, and A. H. MacDonald: Interaction Correction to the Magneto- Electric Polarizability of Z 2 Topological Insulators. Phys. Rev. B 92, (2015), editor s suggestion. Education Graduate and undergraduate studies Ph.D. in Theoretical Physics University of Cologne, Institute for Theoretical Physics Oct 2012 Dissertation: Quantum Hall effect and surface criticality in 3D topological insulators Grade: magna cum laude (1.0) Ph.D. advisor: Prof. Dr. Achim Rosch Diploma in Physics University of Cologne, Institute for Theoretical Physics Jul 2008 Thesis: Quantum Criticality at a Conductance Plateau Transition in a Quantum Wire Grade: 1.1 Thesis advisor: Prof. Dr. Achim Rosch Intermediate Diploma in Physics University of Cologne Sep 2005 Intermediate Diploma in Mathematics University of Cologne Sep 2005 Undergraduate studies of Physics and Mathematics University of Cologne Apr 2003 Jul 2008 Military service Daun, Germany Fernmeldeaufklärungsregiment (FmAufklRgt) 940 Jul 2002 Mar 2003 Abitur Städtisches Gymnasium Kreuzgasse Jun 2002 Grade: 1.0, with distinction (top grade). Diploma thesis Title: Quantum Criticality at a Conductance Plateau Transition in a Quantum Wire Supervisors: Prof. Dr. Achim Rosch Description: We consider a quantum wire with two sub-bands of spin-polarized electrons in the presence of strong interactions. We focus on the quantum phase transition when the second sub-band starts to get filled as a function of gate voltage. Performing a one-loop renormalization group (RG) analysis of the effective Hamiltonian, we identify the critical fixed-point theory as a conformal field theory having an enhanced SU(2) symmetry and central charge 3/2. While the fixed point is Lorentz invariant, the effective speed of light nevertheless vanishes at low energies due to 4/6

5 marginally irrelevant operators leading to a diverging critical specific heat coefficient. Ph.D. thesis Title: Quantum Hall Effect and Surface Criticality in 3D Topological Insulators Supervisors: Prof. Dr. Achim Rosch Description: In the first part, we investigate how a magnetic field induces one-dimensional edge channels when the two-dimensional surface states of three-dimensional topological insulators become gapped. The Hall effect, which can be measured by contacting those edge channels, remains integerquantized even when the topological θ-term in the bulk and the associated surface Hall conductivities are not quantized due to time-reversal symmetry breaking. We show that the quantization of the actual Hall conductivity arises as the θ-term changes by an integer multiple of 2π along a loop around those edge channels. In the second part, we also consider ferromagnetic instabilities of two-dimensional helical Dirac fermions hosted on the surface of three-dimensional topological insulators. We investigate ways to increase the role of interactions by means of modifying the bulk properties which in turn changes both the surface Dirac theory and the screening of interactions. We discuss both the long-ranged part of the Coulomb interactions as well as the effects of local interactions. Both mechanisms can induce spontaneously surface ferromagnetism, thereby gapping the surface Dirac metal and inducing an anomalous quantum Hall effect. We investigate two mechanisms which can naturally lead to small Fermi velocities at the surface and a corresponding small bandwidth when the bulk band gap is reduced. The same mechanisms can, however, also lead to an enhanced screening of surface interactions. While in all considered cases we find that the long-ranged part of the Coulomb interaction is screened efficiently, we also discuss situations, where local interactions induce surface magnetism. Computer skills Programming languages C: very good, 9 yrs of experience C++: good, 6 yrs of experience Python: very good, 2 yrs of experience Fortran, Perl: basic, 1 yr of experience Software skills Linux: very good, 10+ yrs of experience L A TEX: very good, 10+ yrs of experience Mathematica: very good, 8 yrs of experience Languages German: perfect (native speaker) English: fluent Spanish: basic 5/6

6 Notable Interests freiesmagazin: From June 2010 through February 2016 I have worked on a non-profit basis for freiesmagazin a free German magazine with approx thousand readers per month which publishes news and articles from the Linux and Open Source world on a monthly basis. Originally, I started as a typesetter and designer for articles due to my profound knowledge in L A TEX2e. In 2011, I then became a member of the editorial board, where I have been responsible for contacting authors, managing the workflow, and publishing the magazine on a regular basis. 6/6