In lanthanide (Ln) compounds, the localized 4f-electrons usually interact both, with the itinerant spd electrons as well as with each other, leading to a rich variety of unusual properties . Spin-flip scattering of conduction electrons from these 4f local moments may result in their collective magnetic screening below a characteristic temperature called the Kondo temperature Tk. In materials, where local moments are arranged in dense periodic arrays, forming a “Kondo lattice” the deconfinement of localized orbitals through their hybridization with the conduction electrons results in composite low energy excitations. Tuning the hybridization between f orbitals and itinerant electrons can destabilize the Fermi-liquid state towards an antiferromagnetically ordered ground state at a quantum critical point (QCP) [1,2]. However, the emergence of a coherent band of quasiparticles near the Fermi energy in a Kondo lattice system is still not well understood. Additionally, the vast majority of studies have been conducted on 3D bulk materials [1,2]. This PhD project therefore aims at studying quantum criticality in lower dimensions, where potentially larger fluctuations are expected. The scattering of quasiparticles, visualized by spectroscopic Fourier transform of STM conductance maps is used to detect the emergence of quantum entanglement of itinerant substrate conduction and 4f-electrons as a function of temperature in a family of 2D compounds made of arrays of self-organized Ln-atoms on metal substrates..
The possibility of building a 2D lattice of Ln-atoms by monolayer deposition of atoms dressed by ligands, as well as their manipulation with the tip of the STM has been demonstrated by our team . The lanthanide complexes with appropriate ligands are synthesized in the group of M. Ruben (KIT & IPCMS). For this project a dedicated low temperature (LT)-STM equipped with a vector magnetic field is used. The measurements are carried out in ultrahigh vacuum to ensure a clean and reproducible experimental environment [3,4]. The candidate will participate in an ambitious multi-partner project including theoretical support from both, IPCMS and KIT.
Keywords: Molecular electronics, Quantum materials, Scanning tunneling microscopy/ spectroscopy (STM/STS).
Candidate’s profile: We are looking for a highly motivated candidate with a scientific master degree. He/she should have a background in physics and a good knowledge in material science, taste and skills for experimental work. The candidate should be fluent in scientific English. Interested candidates are invited to send a CV, a motivation letter, grades and ranking along with two supporting letters to: [Email Address Removed]
3 year Ph.D. funding (France-German project).
Université de Strasbourg, IPCMS and Karlsruhe Institut für Technologie, INT
 P. Coleman et al., Nature, 433, 226 (2005); S. Sachdev, B. Keimer, Phys. Today, 64, 29 (2011); F. Steglich, Journal of Physics : Conference Series 400, 022111 (2012).
 P. Gegenwart, Q. Si, F. Steglich, Nature Physics, 4, 186 (2008).
 A. Amokrane, S. Klyatskaya, M. Boero, M. Ruben, J.P. Bucher, ACS Nano, 11, 10750 (2017).
 R. Tuerhong, F. Ngassam, S. Watanabe, J. Onoe, M. Alouani, J.P. Bucher, J. Phys. Chem. C 122, 20046 (2018).