Microwave spectroscopy on heavy-fermion systems: probing the dynamics of charges and magnetic moments
Investigating solids with light gives direct access to charge dynamics, electronic and magnetic excitations. For heavy fermions, one has to adjust the frequency of the probing light to the small characteristic energy scales, leading to spectroscopy with microwaves. We review general concepts of the frequency-dependent conductivity of heavy fermions, including the slow Drude relaxation and the transition to a superconducting state, which we also demonstrate with experimental data taken on UPd2Al3. We discuss the optical response of a Fermi liquid and how it might be observed in heavy fermions. Microwave studies with focus on quantum criticality in heavy fermions concern the charge response, …
Microscopic origin of the charge transfer in single crystals based on thiophene derivatives: A combined NEXAFS and density functional theory approach
We have investigated the charge transfer mechanism in single crystals of DTBDT-TCNQ and DTBDT-F4TCNQ (where DTBDT is dithieno[2,3-d;2',3'-d'] benzo[1,2-b;4,5-b']dithiophene) using a combination of near-edge X-ray absorption spectroscopy (NEXAFS) and density functional theory calculations (DFT) including final state effects beyond the sudden state approximation. In particular, we find that a description that considers the partial screening of the electron-hole Coulomb correlation on a static level as well as the rearrangement of electronic density shows excellent agreement with experiment and allows to uncover the details of the charge transfer mechanism in DTBDT-TCNQ and DTBDT-F4 TCNQ, as w…
Back Cover: Microwave spectroscopy on heavy-fermion systems: Probing the dynamics of charges and magnetic moments (Phys. Status Solidi B 3/2013)
Temperature-Dependent Change of the Electronic Structure in the Kondo Lattice System $YbRh_{2}Si_{2}$
Seminar, Deutschland; Journal of physics / Condensed matter 00(00), 1-20 (2021). doi:10.1088/1361-648X/abe479
Crystal growth of new charge-transfer salts based on π-conjugated donor molecules
Abstract New charge transfer crystals of π-conjugated, aromatic molecules (phenanthrene and picene) as donors were obtained by physical vapor transport. The melting behavior, optimization of crystal growth and the crystal structure are reported for charge transfer salts with (fluorinated) tetracyanoquinodimethane (TCNQ-Fx, x=0, 2, 4), which was used as acceptor material. The crystal structures were determined by single-crystal X-ray diffraction. Growth conditions for different vapor pressures in closed ampules were applied and the effect of these starting conditions for crystal size and quality is reported. The process of charge transfer was investigated by geometrical analysis of the cryst…
CCDC 1448360: Experimental Crystal Structure Determination
Related Article: Antonia Morherr, Sebastian Witt, Alisa Chernenkaya, Jan-Peter Bäcker, Gerd Schönhense, Michael Bolte, Cornelius Krellner|2016|Physica B: Condensed Matter(Amsterdam)|496|98|doi:10.1016/j.physb.2016.05.023
CCDC 1448362: Experimental Crystal Structure Determination
Related Article: Antonia Morherr, Sebastian Witt, Alisa Chernenkaya, Jan-Peter Bäcker, Gerd Schönhense, Michael Bolte, Cornelius Krellner|2016|Physica B: Condensed Matter(Amsterdam)|496|98|doi:10.1016/j.physb.2016.05.023
CCDC 1448363: Experimental Crystal Structure Determination
Related Article: Antonia Morherr, Sebastian Witt, Alisa Chernenkaya, Jan-Peter Bäcker, Gerd Schönhense, Michael Bolte, Cornelius Krellner|2016|Physica B: Condensed Matter(Amsterdam)|496|98|doi:10.1016/j.physb.2016.05.023
CCDC 1448361: Experimental Crystal Structure Determination
Related Article: Antonia Morherr, Sebastian Witt, Alisa Chernenkaya, Jan-Peter Bäcker, Gerd Schönhense, Michael Bolte, Cornelius Krellner|2016|Physica B: Condensed Matter(Amsterdam)|496|98|doi:10.1016/j.physb.2016.05.023