Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 17: Poster Session: Correlated Electrons 1
TT 17.8: Poster
Montag, 1. April 2019, 15:00–18:30, Poster D
Kondo lattice: Phase diagrams and Fermi surfaces — •Bishal Poudel1, Sébastien Burdin1, and Gertrud Zwicknagl2 — 1LOMA UMR 5798, 33400, Talence, France — 2Institut für Mathematische Physik, TU Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany
The Heavy fermion (HF) family of materials composed of some rare earth elements (e.g. Ce, Yb, U) such as CeNiSn, CeNi2Ge2, CeRhIn5, CeCoIn5, CePt2In7, UPd2Al3 etc. have partially filled 4-f or 5-f orbitals. In their metallic phase, the effective mass of the charge carriers on these systems can reach up to hundreds times of bare electron mass due to the interaction between conduction elec- trons and the magnetic impurity spins which is known as Kondo effect. Furthermore, these types of materials have very rich phase diagrams with ferromagnetism, anti-ferromagnetism as well as non- conventional quantum phases including superconducting and spin-liquids with application pression [1] or substitution [2].
We will present, our ongoing study of Kondo lattice model (KLM) through mean-field (MF) approxi- mations. Firstly, we will start by detailing our results obtained though the mean-field approximations by the means of ground state phase diagram for 1D “chain”, 2D “square” lattice and 3D “cubic” lattice with respect with the Kondo coupling (JK) and the electronic filling (nc). Our phase diagram includes pure Kondo phase, pure Ferromagnetic phase and some commensurate anti-ferromagnetic phases. At small couping, the phase diagram is dominated by magnetic ordering as predicted Doniach [3] and the phase diagram obtained were also consistent with other several previous studies. Secondly, we will describe the Fermi surfaces obtained for 2D “square” lattice for paramagnetic, ferromagnetic and anti- ferromagnetic phases. This study further puts the foundation for the study of local potential scattering [4] on binary Kondo alloys for paramagnetic phase.
[1] Knebel et al. High-pressure phase diagrams of CeRhIn5 and CeCoIn5 studied by ac calorimetry. Journal of Physics.
[2] Pikul et al. Single-ion kondo scaling of the coherent fermi liquid regime in Ce1−xLaxNi2Ge2. Physical review letters, 108(6):066405, 2012.
[3] S Doniach. The kondo lattice and weak antiferromagnetism. Physica B+ C, 91:231-234, 1977.
[4] Sébastien Burdin and Claudine Lacroix. Breakdown of coherence in Kondo alloys: crucial role of concentration vs band filling. arXiv preprint arXiv:1810.05383, 2018.