Speaker of the IMPRS-CMS

The department uses neutron and X-ray diffraction and spectroscopy as well as optical spectroscopy and Raman scattering to explore the structure and dynamics of materials with strong electron correlations. We also have a strong effort in the development of new spectroscopic methods. As the close collaboration between experimentalists and theorists is essential for progress in this field, a small theory group operates within the department. more

Principal Investigators of the IMPRS-CMS

The Stuttgart Center for Electron Microscopy (StEM) is an internationally recognized center for advanced electron microscopy. The center has a long tradition of applying and developing new microscopy techniques for the investigation of novel materials. The extensive expertise of the researchers and technicians in the group is complemented by a range of instruments; StEM possesses 8 TEMs, including two state-of-the-art Cs-corrected TEMs, 5 SEMs, and a suite of specialized sample preparation equipment.
The group undertakes both independent research and collaborative projects with other groups at the Stuttgart Max Planck Institutes. In heterostructures and functional thin films, StEM investigates structure and chemistry around defects and interfaces at atomic resolution. In bio-composite systems, StEM is studying biologically-driven mechanisms for nanostructure replication and organization. The group has a well-developed program investigating plasmons and electron-interactions, both through experiments and modeling. Many other research projects are described on the StEM webpages. more
The research in the Alavi group is at present largely concerned with the following question: how can one best use a given (finite) amount of parallel computing power in trying to solve electronic (many-particle) Schrodinger equations? We are particularly interested in physical systems in which the electronic wave functions exhibit much irreducible entanglement, in other words cannot be expressed as single configurations (or Slater determinants) in any one-particle basis. As well as being a question of enormous basic significance to theoretical physics and chemistry, the answer to this question impinges on a broad swathe of knowledge: ranging from many-body theory, through to the mathematics of graph theory, optimization and stochastic processes, through to algorithm design and computer science.
As well as, of course, the questions of application. As a graduate student, you will embark on a rigorous course of work which will bring you in contact with each of these areas. Ideal background for this type of work is a good first degree in theoretical physics or chemistry, applied mathematics, or computer science. more
The research in our group is focused on the electronic and magnetic properties of low-dimensional electron systems. Using scanning tunneling microscopy at lowest temperatures (10mK), we study magnetic nanostructures as well as superconductors with very low lying transition temperatures. For example, we utilize the Tedrow-Meservey-Effect (Zeeman splitting in a superconductor) to determine the absolute spin-polarization of tunneling electrons. Furthermore, we use angular resolved photoemission spectroscopy to study the effects of different phenomena (e.g. spin-orbit coupling, defects, and disorder) on the electronic structure of low-dimensional systems. The different materials include topological insulators and graphene. more
The research of our group is concerned with quantum technologies and quantum optics. One particular research focus is quantum networks: we implement quantum protocols, build distributed quantum networks and perform secure quantum computations in them. Furthermore, we work on demonstrating quantum effects in systems with few particles and how to exploit those for applications. Our research is experimental and focuses on photonic quantum systems, meaning we generate, manipulate, and detect single photons.
Furthermore, our research is interdisciplinary and involves aspects from physics, engineering, and computer science. more
The research in our group focuses on the study of transition-metal oxide thin films and multilayers using resonant X-ray spectroscopy. Our goal is to combine different quantum materials in a heterostructure to stabilize new phases with functional properties that can be used, for example, in sensor, memory or logic applications. more
The main research direction concerns the synthesis and characterization of inorganic as well as organic / inorganic multifunctional materials. For the generation of the materials the principles of biomineralization are applied. Within the scope of this research field biomineralizing living systems, like algae or bacteria are investigated. These studies provide the base for the synthesis of functional materials. Beside this work on molecular bionics also the processing of ceramics by the thermolysis of preceramic compounds as well as powder technology and sintering are treated. In addition to that, the characterization of the structure-property relations plays an important role. more
The theory group has a long standing experience in the study of quantum phenomena in the field of atomic, molecular and optical physics. A special focus is on the man-body properties of strongly interacting quantum systems, as naturally realized with dipolar gases, cold atoms in optical lattices, polar molecules, and photons in a Rydberg media. The main research goals are the creation of exotic states of matter with ultra-cold gases, the design of quantum simulators for topological ordered phases and the study of their application for quantum information, as well as the understanding of strongly correlated states. more
Our group investigates correlated electron systems, i.e., materials where interactions between electrons are crucial if we want to understand their properties. We have a certain focus on numerical investigations of model systems: While models are of course a severe simplification of a material, this abstraction implies at the same time that we can use them to test our understanding of the dominant processes and to identify the most important aspects. Current focuses of our research are multi-orbital systems, e.g. iron-based superconductors or iridates, and topological states of matter that arise through electron-electron and electron-spin interactions. more
• All aspects of modern powder diffraction • Structure determination • Thermochromic / Photochromic / Electronic / Magnetic materials • Microstructure • In-situ/time-resolved • Non-ambient conditions • Rietveld refinement • Parametric refinement • Landau theory / Strain-order parameter coupling • Method of Maximum Entropy more
Solid state physics, correlated electron systems, physics of low-dimensional solids, superconductivity, magnetism, molecular physics, organic materials, metallic nanostructures, nanomagnetism, electrodynamics of solids, optical measurements of solids more
Our current research focus is on: nanopropellers and their biomedical applications (ERC: Chiral MicroBots) microrobotics and nanomotors how to construct and power autonomous systems swimming at low Reynolds numbers, hybrid nanocolloids and colloidal molecules single molecule and enzyme based systems the physical chemistry of chirality and chiral nanostructures more
The research in our group is based on computational methodologies from quantum-mechanical up to classical and coarse-grained schemes to investigate the structure and properties of a variety of systems. We are specifically focused on the electronic, transport, and mechanical properties of complex materials ranging from novel two-dimensional structures up to functionalized surfaces and nanopores. It is of our high interest to investigate the change in these properties by applying chemical modifications and structural changes to such materials. In this way, the properties of materials can be selectively tuned and give rise to controllable applications in electronics and nanomechanics. We extend our studies also to the exploration of systems involving materials like the above, biomolecules, and a liquid environment. The interface between those three and their interaction is essential in view of bionanotechnological applications in biosensing and single molecule experiments. more
Our main research direction is the structure and dynamics of the liquid-crystalline state of matter. Liquid crystals are quintessential soft matter materials and provide an excellent testing ground for the advancement of essential concepts in condensed matter science, such as self-organization, phase transitions, hydrodynamics and elasticity. Systems exhibiting liquid crystalline order range from small rod- or disc-shaped organic molecules (e.g., the ‘classic’ liquid crystals used in LCD devices), over polymers, dispersions of micelles and nanoparticles (e.g., CNTs and viruses) to certain quantum electronic materials. Our research aims to elucidate the relations between the molecular structures, the symmetry and order parameters of liquid crystalline ordering, and the macroscopic properties of liquid crystals. We are particular interested in the unique chirality effects in liquid-crystalline systems, leading to self-organized chiral nanostructures which e.g. mimic the liquid-crystalline structures found in biological matter. more
Plasmonic materials that consist of nanostructured metals concentrate light on a subwavelength scale. Optical nanoantennas focus light fields into spots of less than 100 nanometers. When arranged in suitable geometries, such plasmonic metamaterials can act as electrical nanocircuits and provide a toolbox to tailor both electric and magnetic light fields which can even result in a negative refractive index and optical cloaks. Chiral plasmonic structures and metamaterials can serve as broadband waveplates and circular polarizers. In combination with suitable surfaces, the nanooptical materials can act as nanosensors that give unprecedented sensitivity and selectivity in the atto- and zeptomolar range, even down to the single monolayer or molecular level. Applications such as hydrogen or glucose sensing based on optical elements have been pioneered in our group. Angle- and polarization independent perfect absorbers can also serve in this role. We manufacture and characterize our nanostructures in our own 600 m2 state of the art nanofabrication facility with electron beam lithography, evaporation and dry etching, as well as nanoscale analysis and imaging capabilities including scanning electron and atomic force microscopy. In our cleanroom we have pioneered three-dimensional stacking of metamaterials, as well as electroless metallization of photonic nanostructures that have been fabricated by 3D direct laser writing. Additionally, colloidal lithography with titled angle evaporation was pioneered by our group to manufacture cm2 sized homogeneous plasmonic structures and metamaterials at extremely low costs. more
Polarized x-ray based studies on magnetism and modern magnetic materials utilizing X-ray magnetism circular dichroism (XMCD) and related techniques, like X-ray resonant reflectivity (XRMR), and X-ray spectroscopic microscopy. The main focus from technological and from basic research points of view, the investigation of modern magnetic bulk and thin film systems. This includes thin film heterostructures of magnetic and nonmagnetic multilayers in combination with high-tc superconductors. Related research topics are interface magnetism, magnetocrystalline anisotropy, orbital moments, nano-magnetism, spin conduction and relaxation, interfacial exchange interaction, room temperature ferromagnetism in nominal d0 magnets, and exchange bias. Due to strong future demands on high performance permanent magnets, we started investigations on new phase rare earth – transition metal based magnets, with high energy products, and on MnBi based high temperature compatible. more
We search for new ways of manipulating modern quantum materials using strong ultrashort light pulses in order to control emergent physical properties such as photo-induced superconductivity and find new functionalities of dynamically driven matter. Therefore we apply advanced nonlinear optical methods, most prominent ultra-broad band pump-probe spectroscopy, to investigate ultrafast quantum many body dynamics in complex solid-state materials. Combining these methods with high-resolution optical near-field microscopy we can access and manipulate such dynamics even with sub-wavelength resolution down to the nanoscale. more
Nanoscience and nanotechnology; surfaces and interfaces; self-organisation phenomena and epitaxial growth; fabrication and characterization of metal, semiconductor and molecular nanostructures; molecular electronics; carbon nanotubes and graphene; clusters and nanocrystals; interactions and processes on the atomic and molecular scale; scanning probe microscopy and spectroscopy; nanooptics more
Research in the Organic Electronics group focuses on novel functional organic materials and on the manufacturing and characterization of organic and nanoscale electronic devices, such as high-performance organic thin-film transistors, carbon nanotube field-effect transistors, and inorganic semiconductor nanowire field-effect transistors. Of particular interest is the use of molecular self-assembled monolayers in functional electronic devices. We are developing materials and manufacturing techniques that allow the use of high-quality self-assembled monolayers as the gate dielectric in low-voltage organic and inorganic field-effect transistors and low-power integrated circuits on flexible substrates. more
Synthesis, characterization and application of novel liquid crystalline materials (discotics, crown ethers, ionic liquid crystals), synthesis of cross-linkers for biocompatible hydrogels, synthesis of novel functional dyes, development of methods for stereoselective synthesis, enzymes in organic synthesis (lipases, cytochrome P450 monooxygenases), total synthesis of natural products and investigation of the mode of action, transition-metal-catalyzed C-C couplings and oxidations, biomimetic synthesis more
Our research is geared towards the rational synthesis of new multifunctional materials with engineered properties by combining the tools of solid-state and nanochemistry. We aim at creating function from both atomic-scale structure and nanoscale morphology, with a strong emphasis on exploring structure-property relationships based on a variety of diffraction and spectroscopic techniques. Specifically, we invoke the concepts of soft chemistry and directed self-assembly to develop new two-dimensional systems, porous frameworks, photonic nanostructures and layered heterostructures with application potential in sensing, catalysis, as well as photo- and electrochemical energy conversion and storage. more
One of the main aims of the interdisciplinary research team of Prof. Ludwigs at the Institute of Polymer Chemistry is to understand and control structure-function relations in Functional Polymeric Materials which have potential use in applications such as photoactive layers in organic solar cells or membranes in batteries.
The group pursues design on the molecular scale by synthesizing polymers with tailor-made properties. Organization on the mesoscopic scale is directed by using concepts such as self-assembly of block copolymers and the crystallization of semicrystalline polymers. Physical and physicochemical characterization expertise include electrochemical (e.g. CV, in-situ spectroelectrochemistry), electrical (FET measurements) and spectroscopic methods. more
From a fundamental point of view, thermodynamics and kinetics of ionic charge carriers are to the fore (solid state ionics). Special emphasis is put on interfacial effects and size effects (nanoionics). Typical questions to be answered are: What are the mechanisms of ion conduction? How can concentrations of charge carriers be varied, optimized and modeled? How to come up with improved materials? From an applied point of view the research is concerned with electrochemical devices such as lithium-based batteries, fuel cells and chemical sensors. Typical problems to be solved refer to the design of optimized electrodes and electrolytes, but also the conception of novel storage and sensing mechanisms. more
The department explores interfaces in complex materials to create and understand new electronic systems, materials, and novel physical phenomena. This work is fundamental science in an area that is also of interest for possible applications. Complex oxide heterostructures are synthesized on the atomic scale by using advanced epitaxial growth techniques. Lateral confinement on the nanometer scale, for example by e-beam lithography, is applied to create complex 1D and 0D electronic systems. The department is furthermore striving to understand and advance thermoelectronic energy conversion, with the goal of creating a method to convert with very high efficiency solar radiation or heat into electricity. more
The research in my group is mainly focused on non-equilibrium phenomena in Quantum Materials as well as on novel Josephson and Proximity effects using triplet superconductors. One major direction of our actual investigations are Higgs oscillations in superconductors under non-equilibrium conditions.
Employing various non-equilibrium techniques we have predicted unique effects that provide novel insights into unconventional superconductors. We collaborate with many experimental groups in Stuttgart as well as in Toyko and Vancouver within the framwork on the Max Planck--UBC--UTokyo Center for Quantum Materials.
With the prediction of novel and Josephson and Proximity effects in triplet junctions my group has opened a new field of research in condensed matter physics.
Recent experimental progress in thin film technology allows now to fabricate these devices as well as SQUIDS and new hetrostructures. Furthermore, we also work on non-centrosymmetric superconductors that reveals a mixture of singlet and triplet pairing. more
In the Quantum Many-Body Theory department, electronic properties of solids are analyzed and computed with a main emphasis on systems where electronic correlations play a crucial role, such as high temperature superconductor and other transition metal oxides. Besides bulk properties of one-, two- and three-dimensional systems also surface states of topological phases, as well as problems with a mesoscopic length scale such as quantum dots, quantum wires, and quantum Hall systems are being studied. The correlation problem is treated by various modern numerical and field-theoretical techniques. more
The main research direction of the institute concerns the fabrication, characterization and study of new kinds of non-classical light sources, e.g. single-photon and entangled-photon sources and different kinds of semiconductor lasers. A special focus lies on their quantum optical properties and their applications in quantum information technology. Further goals are the study of resonator quantum electrodynamics effects in semiconductors. Here an ultimate goal is to develop methods to couple two or more quantum dots via high-quality modes of photonic cavities. We also have a strong effort on the epitaxial growth of semiconductors (MOVPE, arsenides, phospides, nitrides) and their structuring to novel photonic devices and circuits. more
The work focuses on synthesis and detailed characterization of metal-rich compounds, preferentially containing nitrogen as a constituent. First emphasis is the design and development of preparative techniques as basis for synthesis of novel materials. Special attention is granted to structural characterization, electronic and magnetic properties as well as mechanical and chemical behavior. These data are inevitable for any detailed consideration of chemical bonding and potential applications. • Advanced solid state synthesis of functional materials including various high pressure techniques, solvothermal synthesis and crystal growth, high temperature synthesis • Solid state reaction pathways and crystal growth mechanisms • Magnetic and superconducting materials, ionic conductors more
Controlled quantum correlations are at the heart of emerging quantum technologies. Atomic physics offers ultracold single atoms or ions which are studied in that context very successfully. Mostly due to the requirement of ultralow temperatures the scaling to a large number of interconnected devices is difficult. Mesoscopic ensembles of atoms which can be well controlled in their geometry and which provide coherent long range interactions promise a significant simplification for quantum devices and networks (key words: Quantum Gases, Quantum optics, Atom optics, Atomic physics). more
Materials with strong electronic correlations are amongst the most intriguing topics at the forefront of research in condensed matter physics. On the one hand, they exhibit fascinating phenomena like quantum criticality and high-temperature superconductivity, bearing a high potential for applications. On the other hand, they are theoretically very appealing due to their limited understanding, even on the very fundamental level. Within the research group “Theory of Strongly Correlated Quantum Matter”, starting from September 2020, the frontier of this fundamental understanding is pushed by applying cutting-edge numerical quantum field theoretical methods to quantum critical systems, high-temperature superconductors, Mott insulators and magnetically frustrated systems, both in the purely model (Hubbard model, periodic Anderson model) as well as material oriented (heavy fermions, cuprates, organics)
context. more
Our team concentrates on the nanoanalysis of interreactions. We are experts in atom probe tomography to investigate solid-state processes in single-atom sensitivity and resolution. Presently, innovative instruments are developed to study the chemistry of solid/liquid interfaces with the same methods. From the perspective of materials physics, short-circuit atomic transport along triple junctions or other higher order defects in complex materials are of particular interest. We are running a sputter deposition laboratory to produce required model structures from metallic thin films and metallic nanowires. We assemble promising all-solid-state batteries and sensor devices. Theoretical work is performed by Molecular Dynamics or Monte-Carlo simulation to predict field evaporation and emission from nanometric tips.  Furthermore, we study thermodynamic properties of topologically necessary defects and the mechanical stability of thin films by theoretical methods. more
Our research group studies electronic and magnetic structures of quantum materials. A special focus is on topological materials, which exhibit unusual properties, such as exotic surface states and anomalous transport phenomena, that are unaffected by continuous deformations, e.g., stretching, compressing, or twisting. Our aim is to develop a theoretical framework to describe these topological properties, and to find new ways how to use them in the laboratory and for device applications. We seek to classify topological materials in terms of symmetries and to discover new remarkable examples. Current research priorities focus on the topological properties of nodal-line semimetals, quantum magnets, and unconventional superconductors, which we study using both analytical and numerical techniques. more
We focus on the spectroscopic and magnetic study of molecular nanomagnets. These materials have been proposed for applications in fields ranging from quantum computing to magnetic data storage. We are especially interested in understanding the transition from the microscopic quantum mechanical world of small particles to the macroscopic classical world that we live in. We specialize in advanced spectroscopic studies, including those based on electron spin resonance-related techniques, to investigate the magnetic anisotropy and quantum coherence and their origins. more
Research in the Solid State Nanophysics Group focuses on the study of the many unusual ways in which electrons organize themselves as a result of interactions and correlations among their charge and spin degrees of freedom, when these electrons are confined in one or more dimensions on the nanometer scale. Transport and optical properties are investigated with local probe methods, at low temperatures, in high magnetic fields, under high frequency radiation or any combination thereof. The electrons are confined either in III–V semiconductor heterostructures or in strictly two-dimensional crystals such as graphene or other single layers of the large class of layered materials with weak interlayer forces. Also hybrid stacks of these two-dimensional crystals are fabricated and explored in a quest for novel functionalities and interaction physics. more
In our group we study the atomic and electronic structure of solid surfaces and 2D materials. A strong focus of the research is the growth and functionalization of epitaxial graphene on Silicon Carbide. By means of atomic intercalation we can tailor graphene’s electronic properties. We use angle-resolved photoemission spectroscopy (ARPES) to investigate doping and renormalization of the π-bands in graphene – in the home lab and at synchrotron facilities. Structured SiC substrates are the basis to grow epitaxial graphene nanoribbons with a one-dimensional electronic spectrum. The interaction of hetero-epitaxial 2D materials (e.g. transition metal dichalcogenides) and molecular layers with the graphene and its influence on both, the graphene and the 2D layer is studied with a multitude of surface science methods in ultra-high vacuum. more
Entanglement of electrons (electron correlations) in solids, in combination with details of the crystal lattice structure, produce a surprisingly rich variety of electronic phases, that are liquid, liquid-crystal and crystalline states of the charge and spin degrees of freedom. These complex electronic phases and the subtle competition among them very often give rise to novel functionality. The department will be studying these interesting novel phases in transition metal oxides and related compounds where the narrow d-bands, which give rise to strong electron correlations, in combination with the rich chemistry of such materials provides excellent opportunities for new discoveries. The goal of this research will be to hunt for new materials exhibiting exotic electronic states of matter, showing phenomena such as superconductivity or high thermoelectricity, and to explore them with advanced measurement techniques to unveil the physical mechanisms that could be drivers of potentially highly desirable functionality. more
Electrical transport through single and coupled quantum dot systems (single-electron charging, Kondo physics) have been a long lasting topic. Furthermore, a scanning force microscope has been operated at 1.4 K to extract Hall potential profiles and current distributions in quantum Hall samples. Recently we have enhanced our abilities by a scanning probe microscope - operated below 0.1 K - using an array of single-electron transistors as probes. Being responsible for the Nanostructuring Lab of the institute, the fabrication of functional nanostructures for electronic, plasmonic or optical applications using state-of-the-art electron beam lithography became a major task. more
The group capitalizes on generating synthetic spin systems in solids envisioning their precise quantum optical control. In the course of that research, spin arrays in insulators like e.g. diamond are generated and individual spin states are controlled. The systems provide a means to understand and develop control mechanisms in complex interaction many particle systems. Specifically engineered spin states are used for ultraprecise field measurements. Solid state quantum optics and magneto optics commences via integration of those structures in cavities and plasmonic resonators. Among the major long term research goals is the integration of mechanical and spin systems with the aim to explore the quantum mechanics of hybrid quantum systems with a large degree of freedom and precise unitary control. more
Go to Editor View