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PD Dr. Hans-Gregor Hübl

Photo von Dr. rer. nat. Hans-Gregor Hübl.
Phone
+49 89 289-14204
Room
E-Mail
hans.huebl@tum.de
Links
Homepage
Page in TUMonline
Group
Technical Physics
Job Title
PD at the Physics Department

Courses and Dates

Title and Module Assignment
ArtSWSLecturer(s)Dates
Magnetism
eLearning course course documents
Assigned to modules:
VO 2 Hübl, H. Tue, 14:00–15:30, virtuell
Spin Currents and Skyrmionics
course documents
Assigned to modules:
PS 2 Hübl, H.
Assisstants: Althammer, M.Geprägs, S.Opel, M.
Thu, 14:00–15:30, virtuell
Topical Issues in Magneto- and Spin Electronics
course documents
Assigned to modules:
HS 2 Brandt, M. Hübl, H.
Assisstants: Althammer, M.Geprägs, S.
Wed, 11:30–13:00, virtuell
Exercise to Magnetism
eLearning course course documents
Assigned to modules:
UE 1 Hübl, H. dates in groups
Revision Course to Topical Issues in Magneto- and Spin Electronics
Assigned to modules:
RE 2
Responsible/Coordination: Hübl, H.
Revision Course to Spin Currents and Skyrmionics
Assigned to modules:
RE 2
Responsible/Coordination: Hübl, H.

Offered Bachelor’s or Master’s Theses Topics

Controlling magnon transport in antiferromagnetic insulators
In antiferromagnetic insulators, we obtain two magnon modes with opposite spin chirality due to the two opposing magnetic sublattices. In this way, magnon transport in antiferromagnetic insulators can be considered as the magnonic equivalent of spin transport via electrons. The aim of this thesis is to obtain a better understanding of the magnon transport in antiferromagnetic insulators and investigate external control parameters that allow a manipulation of the spin information transport in the antiferromagnetic insulator. Moreover, these experiments allow to extract important transport properties like for example the magnon spin life-time. We are looking for resourceful master student heavily interested in these magnon transport experiments. In order to answer questions regarding magnon transport in magnetic insulators, your thesis will contain aspects of the fabrication of nano-scale devices using electron beam lithography as well as ultra-sensitive low-noise electronic measurements in a cryogenic environment.
suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Rudolf Gross
Elektronenspindynamik in einer stark koppelnden Umgebung

Modern quantum circuits allow to study strong light-matter interaction in a variety of systems. This so-called strong-coupling regime is key for many aspects of quantum information processing. This project focusses on strong coupling between a paramagnetic electron spin ensemble and a superconducting microwave resonator. Strong coupling is an established phenomenon in this system. However, many aspects regarding the dynamics of this coupled system as well as the non-linear response properties are not fully understood, yet, and we will address these aspects within this project. For this project, we will use superconducting microwave resonators based on NbTiN and spin paramagnetic spin ensembles of phosphorous donors and erbium centers in silicon.

 

We are looking for a highly motivated master student joining this project. Within your thesis, you will address questions regarding the dynamic response of a strongly coupled system based on a paramagnetic spin ensemble and a microwave resonator. In this context, you will fabricate and optimize microwave resonators and operate them at cryogenic temperatures. In addition, you will use complex microwave pulses, to control the coupled system and experimentally investigate its dynamical response. Within the project, you will learn how to fabricate superconducting microwave resonators in our in-house cleanroom and how to synthesize microwave pulses using arbitrary waveform generators

suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
  • Master’s Thesis Quantum Science & Technology
Supervisor: Hans Hübl
Quantum acoustics in novel piezoelectric multi-layer systems
The field of quantum acoustics aims to investigate quantum mechanical effects in acoustic resonator structures. Combined with e.g. optical and / or superconducting circuits, this offers the possibility to create quantum hybrid systems, which are discussed in the context of storing and converting quantum states. In this project, we shall investigate one of the building blocks, i.e. the surface acoustic wave (SAW) resonator. With your help, we aim to develop and optimize SAW resonators operating in the GHz frequency range with high quality factors and test these devices at moderately low (3-10K) and millikelvin temperatures. Your bachelor thesis will bring you in touch with state-of-the-art nanofabrication technology and introduce you to microwave spectroscopy tools like vector network analyzers, as well as cryogenic measurement environments. Careful data analysis of the transmission and reflection data of these resonators combined with modeling will put you in the position, to make a meaningful contribution to the creation of quantum hybrid systems.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Hans-Gregor Hübl
Quantum acoustics in the giant atom limit
The field of quantum acoustics aims to investigate the interaction between matter and sound, in a similar way that quantum optics (QO) studies the interaction between matter and light. In detail, we enable this interaction using surface acoustic waves (SAWs) and artificial atoms (Qubits) formed by superconducting quantum circuits. Quantum acoustics offer interesting differences to quantum optics. The propagation speed of sound in solids is approximately five orders of magnitude slower than for light in vacuum, leading to the SAWs much shorter wavelengths compared to electromagnetic waves. This allows the exploration of the “giant atom” regime in which the size of the artificial atoms becomes comparable to or larger than the wavelength of the interacting wave. In this regime, interesting physics like interference and non-exponential decay of quantum states become accessible. We are looking for a motivated master student for a master thesis in the context of quantum acoustics. The goal of your project is to investigate the static and dynamic interplay between surface acoustic waves and one (or more) superconducting qubits. Your thesis project includes the fabrication of aluminium-based superconducting circuits on silicon and lithium niobate using state-of-the-art nano-lithography and metal deposition techniques. Subsequently, these circuits shall be experimentally investigated in a cryogenic microwave measurement setup. As such, the project will allow you to gather expertise in quantum physics, nanofabrication, microwave engineering, and cryogenic techniques.
suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
  • Master’s Thesis Quantum Science & Technology
Supervisor: Hans-Gregor Hübl
Superconducting devices based on superconductor/ferromagnet heterostructures
The combination of ferromagnetic and superconducting materials leads to intriguing proximity effects at the interface of the two materials. The goal of this thesis is to investigate the spin transport of superconductor/ferromagnet interfaces and model the obtained results in the framework of proximity effects. To this end, we will fabricate superconducting devices based on superconductor/ferromagent heterostructures with a special focus on controlling magnetization dynamics via superconducting charge currents. This requires investigations at low temperatures around the critical temperature of the superconductor in large magnetic fields. In addition microwave magnetic fields will be employed to drive magnetization dynamics in the ferromagnet and excitations in the superconductor. We are looking for a talented master student to investigate spin transport in superconductor/ferromagnet heterostructures. You will fabricate superconductor/ferromagnet heterostructures using our new UHV sputtering system. As a next step, you will structure these blanket films with optical and electron beam lithography into superconducting devices. Finally, you will characterize your fabricated samples at low temperatures utilizing superconducting magnet cryostats. Here, high frequency spin dynamics as well magnetotransport studies are the focus of your thesis.
suitable as
  • Master’s Thesis Condensed Matter Physics
  • Master’s Thesis Applied and Engineering Physics
Supervisor: Rudolf Gross
Tailoring magnon transport in magnetic insulators
By reducing the dimension of materials we can enter into the world of novel quantum classes of materials. Especially, in the limit of 1-dimensional transport, fascinating phenomena like the quantization of transport properties are observed. With your Bachelor thesis you will advance our magnon transport experiments in thin film magnetic insulators by further reducing the lateral dimensions of the magnon transport channel. Utilizing scanning probe microscopy, you will analyze the surface topography of the structured devices, magnetic properties and optimize the fabrication processes. You will utilize sophisticated nano-lithography in combination with state-of-the-art thin film deposition techniques to constrain the magnon transport channel in magnetic insulators. In addition, you will gain insight into scanning probe microscopy, one of the frontrunners for surface spectroscopy analysis.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Hans-Gregor Hübl
Ultra-sensitive microwave spectroscopy setup for electron spin resonance
Planar superconducting microwave resonators are key for the ultra-sensitive detection of spin properties. We employ planar microwave resonators fabricated from various superconducting materials like Nb, NbN and NbTiN and test their performance with respect to field and temperature stability. With your help, we aim to improve our resonator design and test their performance with an existing variable temperature setup operating between 1.5 and 300K. You shall further asses the overall performance of the setup using electron spin resonance. Your bachelor thesis will bring you in touch with state-of-the-art microwave spectroscopy tools like vector network analyzers, as well as cryogenic measurement environments. In addition, you will fabricate and optimize microwave resonators and perform the microwave spectroscopy measurements. Moreover, the careful data analysis of the magnetic field dependent datasets will put you in the position, to make a meaningful impact on novel spin resonance spectroscopy approaches.
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Hans-Gregor Hübl
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