Join us in the exploration of physics at the atomic scale!
The Loth group is inviting students to apply for Master thesis (MSc) projects in quantum nanoscience.
You will directly participate in state-of-the-art research in quantum nanoscience. In addition to conducting fascinating experiments here in Stuttgart, you will have the chance to participate in at least one major conference such as the Spring meeting of the DPG and build contacts in our network of nanoscience research groups around the world for possible stays abroad.
We have several thesis projects available in the general field of scanning probe microscopy at the nanoscale. The projects span a wide range of different topics from instrument design over experimental investigations to theoretical modelling. Below are specific projects we offer to you. However, we are open to develop a project tailored to your interests and skills. Don’t hesitate to contact us, together we will find the perfect project for you!
Electron spin resonance spectroscopy of individual molecules
In this cutting-edge project, we will use electron spin resonance spectroscopy (ESR) in a state-of-the-art scanning tunneling microscope (STM) to achieve quantum control of the spin of individual atoms and molecules on a surface. This new technique has recently achieved unprecedented combination of spatial, temporal and energy resolution. In this project you will extend this method to designer molecules that are candidates for molecular quantum processors. The aim is to understand and control single molecular spins and to ultimately build networks of these qubit-candidates. This thesis is part of the Loth group’s research in the Center for Applied Quantum Technology, ZAQuant.
A relevant paper for this project from our group can be found here (S. Baumann et al, Science, 2015).
Atomic-scale generation of coherent acoustic phonons
Recent experiments with our ultrafast scanning tunneling microscope showed that tip-enhanced Terahertz fields generate extremely localized femtosecond forces. These forces excite coherent acoustic phonons at the atomic scale enabling a new way to control matter dynamically. In your thesis, you will use this new method to measure coherent acoustic phonons in atomically designed nanostructures and two-dimensional materials and thereby gain understanding of localized phonon modes and electron-phonon interaction. This thesis is part of the Loth group’s ultrafast imaging laboratory at the FMQ.
If you are interested you could dive into our recent work here (S. Sheng et al, PRL, 2020).
Next to our experimental investigations of acoustic phonons, we also conduct theoretical modelling of the measurable dynamics. The interworking of simulation and experiment is key for prediciton and interpretation of experimental results. A purely experimental thesis as well as a theoretical approach, or a combination thereof would be feasible for this project.
Quantum stochastic resonance of atomically assembled nanomagnets
Our group has recently developed a new measurement technique that allows for the full characterization of multi-level quantum systems over a broad frequency range from kHz to more than 10 GHz, called stochastic resonance spectroscopy. You will apply this novel technique to quantum magnets that you assemble atom-by-atom on a surface. On these nanostructures, you will investigate the fundamental quantum mechanical processes that cause decoherence and quantum tunneling of the magnetization. The goal of the thesis will be to map out the transition from quantum to classical behavior in nanostructures. This thesis is part of the Loth group’s research in the Center for Applied Quantum Technology, ZAQuant.
If interested: we have several publications on this topic in preparation, but some initial results can be found here (M. Hänze et al, Science Advances, 2021).
Coupling a tunable laser for resonant excitation of single molecules
You will develop and implement a new optics design that couples a highly tunable laser source to the tunnel junction of a scanning tunneling microscope. You will characterize this setup aiming at a measurement of atomically localized generation and dynamics of excitons and photoelectrons in molecules and 2D semiconductors. This project is part of the Loth group’s next-generation scanning probe microscopes that will explore light-matter interaction with unprecedented precision at the atomic scale.
Light matter interaction is at the forefront of scanning probe microscopy at the moment and we want to extend our experimental capabilities in this direction as well. This thesis will involve significant instrumental development, setup work and programming capabilities in order to interface the new laser system with our existing setup.
Implementation of microwave excitation in a Millikelvin Atomic Force Microscope (AFM) for ultrafast measurements
Our most advanced experimental tool, an atomic force microscope operating at mK temperatures, is still in its setup phase. With this new setup we want to achieve coherent manipulation of individual atoms and molecules featuring long coherence times on insulating substrates. To that end, you will implement a new low-dissipation design idea for microwave transmission lines that can inject ultrafast signals into a state-of-the-art scanning probe microscope operating at 50 mK temperature. You will use this setup to perform spectroscopy of molecular and atomic qubits with atomic spatial resolution. This thesis is part of the Loth group’s research in the Center for Applied Quantum Technology, ZAQuant.
This project can open up an entirely new research direction, instrumental development skills are necessary in order to succeed.
Charge Density Wave modelling and experimental investigation
Join into our theoretical modelling of charge density wave dynamics. Advance our model and simulation code to a full quantitative simulation of our experiments. Test and optimize the Simulation. Use experimental data to obtain the empirical simulation parameters and to test the validity of simulation results. Develop interesting experiments with the use of the simulation. If you want to conduct experiments yourself, join us in the lab, to investigate a charge density wave system with our ultrafast laser-coupled scanning tunneling microscope.
Our puplication of previous investigations of charge density wave dynamics is currently under review.
Are you interested?
Then, please get in touch with us. Send us an email to office@fmq.uni-stuttgart.de, contact Sebastian Loth or Susanne Baumann directly, or simply come by. You’ll find us on the 6th floor of Pfaffenwaldring 57.
Susanne Baumann:
susanne.baumann@fmq.uni-stuttgart.de
+49 711 685 61688
Sebastian Loth:
sebastian.loth@fmq.uni-stuttgart.de
+49 711 685 65252
Contact
Sebastian Loth
Prof. Dr.Head of Institute FMQ1 (managing director)