akemper at ncsu.edu
….Partners III, Room 149
NC State University, Department of Physics
851 Main Campus Dr., Raleigh NC 27606.
Dr. Kemper received his PhD in Physics in 2010 from the University of Florida. He spent 2 years as a postdoctoral research at Stanford University and SLAC National Laboratory followed by serving as an Alvarez Fellow at Lawrence Berkeley National Laboratory before joining the faculty at NC State in 2015 as an assistant professor.
During his PhD studies and continuing during his postdoctoral career, he used computational techniques to study the high-Tc cuprate superconductors, and the novel Fe-based superconductors that were discovered in 2006. Using a combination of Density Functional Theory, Quantum Cluster methods and computational modeling he addressed several aspects of the normal and superconducting states in these materials. Of particular note are a study of the gap symmetry in the Fe-based superconductors, as well as a joint experimental-theory paper showing the presence of four-fold symmetry breaking above the ordering temperatures in Co-doped BaFe2As2.
Starting during his postdoctoral career, and continuing now at NC State, he has embarked on a separate research project in non-equilibrium physics of complex materials. Non-equilibrium phenomena are studied experimentally using ultrafast lasers, which perturb the material under study and observing the subsequent dynamics. He has developed a set of software tools that theoretically model the pump-probe process in a variety of systems, which has to the first theoretical examinations of the pump-probe process. This has led to a series of works answering fundamental questions in non-equilibrium physics as well as collaborative works with experimentalists using pump-probe techniques to answer questions in materials physics.
Select Publications | Complete List Of Publications
H. Hubener, M. A. Sentef, U. De Giovannini, A. F. Kemper, and A. Rubio, Creating stable floquet-weyl semimetals by laser-driving of 3d dirac materials, Nat. Comm., 8, 13940, (2017). link
J. D. Rameau, S. Freutel, A. F. Kemper, M. A. Sentef, J. K. Freericks, T. Avigo, M. Ligges, L. Rettig, Y. Yoshida, H. Eisaki, J. Schneeloch, R. D. Zhong, Z. J. Xu, G. U. Gu, P. D. Johnson, and U. Bovensiepen, Energy dissipation from a correlated system driven out of equilibrium., Nat. Comm. 7, 13761, (2016). link
C. Jozwiak, J. A. Sobota, K. Gotlieb, A. F. Kemper, C. R. Rotundu, R. J. Birgeneau, Z. Hussain, D. H. Lee, Z. X. Shen, and A. Lanzara, Spin-polarized surface resonances accompanying topological surface state formation, Nat. Comm., 7, 13143, (2016). link
M.A. Sentef, A.F. Kemper, A. Georges and C. Kollath., Theory of light-enhanced phonon-mediated superconductivity, Phys. Rev. B, 93, 144506, (2016). link
Shuolong Yang, J.A. Sobota, D. Leuenberger, A.F. Kemper, J.J. Lee, F.T. Schmitt, W. Li, R.G. Moore, P.S. Kirchmann, and Z.-X. Shen, Thickness-Dependent Coherent Phonon Frequency in Ultrathin FeSe/SrTiO3 Films, Nano Lett. 15 (6), (2015). link
A.F. Kemper, M. A. Sentef, B. Moritz, J. K. Freericks, and T. P. Devereaux, Amplitude Mode Oscillations in Pump-probe Photoemission Spectra of Electron-phonon Mediated Superconductors, Phys. Rev. B. 92, 224517 (2015). link
MA Sentef, M Claassen, AF Kemper, B Moritz, T Oka, JK Freericks, TP Devereaux, Theory of Floquet Band Formation and Local Pseudospin Textures in Pump-probe Photoemission of Graphene, Nat. Comm. 6 (2015). link
A.F Kemper, MA Sentef, B Moritz, JK Freericks, TP Devereaux, Effect of Dynamical Spectral Weight Redistribution on Effective Interactions in Time-resolved Spectroscopy, Phys. Rev. B, 90, 075126 (2014). link
JA Sobota, SL Yang, AF Kemper, JJ Lee, FT Schmitt, W Li, RG Moore, James G Analytis, Ian R Fisher, Patrick S Kirchmann, Thomas P Devereaux, Z-X Shen, Direct Optical Coupling to an Unoccupied Dirac Surface State in the Topological Insulator Bi2 Se3, Phys. Rev. Lett. 111 (13), 136802 (2013). link
M Sentef, AF Kemper, B Moritz, JK Freericks, ZX Shen, TP Devereaux, Examining Electron-boson Coupling Using Time-resolved Spectroscopy, Phys. Rev. X 3 (4), 041033 (2013). link
PS Kirchmann, O Krupin, M Yi, M Langner, N Huse, JS Robinson, Y Chen, SY Zhou, G Coslovich, B Huber, DA Reis, RA Kaindl, RW Schoenlein, D Doering, P Denes, WF Schlotter, JJ Turner, SL Johnson, M Först, T Sasagawa, YF Kung, AP Sorini, AF Kemper, B Moritz, TP Devereaux, D-H Lee, ZX Shen, Z Hussain, Phase Fluctuations and the Absence of Topological Defects in a Photo-excited Charge-ordered Nickelate , Nat. comm. 3, 838 (2012). link
M Yi, D Lu, JH Chu, JG Analytis, AP Sorini, AF Kemper, B Moritz, SK Mo, Rob G Moore, Makoto Hashimoto, Wei-Sheng Lee, Zahid Hussain, Thomas P Devereaux, Ian R Fisher, Zhi-Xun Shen., Symmetry-breaking Orbital Anisotropy Observed for Detwinned Ba (Fe1-xCox) 2As2 above the Spin Sensity Wave Transition, PNAS 108, 6878 (2011). link
AF Kemper, TA Maier, S Graser, HP Cheng, PJ Hirschfeld, DJ Scalapino., Sensitivity of the Superconducting State and Magnetic Susceptibility to Key Aspects of Electronic Structure in Ferropnictides, New J. Phys. 12, 073030 (2010). link