CONTROL AND DYNAMICS OF QUANTUM MATERIALS

Spin-orbit Coupling, Correlations, and Topology

© Simon Wegener

News & Events

News

Archive

  • Corinna Kollath  is APS fellow

    Corinna Kollath became fellow of the American Physical Society in 2020 "for studies of low dimensional correlated systems, in particular out of equilibrium, using a combination of analytic and novel numerical approaches".

    Congratulations!

     

  • Dispersions of many-body Bethe strings observed

    Theoretical physicist Hans Bethe predicted in 1931 that complex bound states of magnons – Bethe strings – could exist in one-dimensional quantum magnets. After the first experimental observation in 2018, Dr. Zhe Wang (Institute of Physics II, University of Cologne) together with colleagues from Berlin, Cologne, Didcot, Dresden, Grenoble, Mumbai, Shanghai and Vancouver now report further experimental evidence for the existence of the many-body string states in a one-dimensional quantum magnet in the journal Nature Physics.

     

  • Walter Schottky prize for Zhe Wang

    Dr. Zhe Wang receives the Walter Schottky prize "For his pioneering work in the field of quantum magnetism, in particular for the experimental detection of so-called Bethe strings using THz spectroscopy at very high magnetic fields."

     

    press release

Events

© Simon Wegener

RESEARCH PROFILE

COLLABORATIVE RESEARCH CENTER 1238

Control and Dynamics of Quantum Materials

Spin orbit coupling, correlations, and topology

Advances in materials science are one of the strongest drivers of technological innovations and thereby shape our daily life, though often in an unseen way. Powerful examples from recent years include the advent of novel memory technologies building on magnetoresistance read/write heads, ferroelectric, and phase-change memories. The discovery of fascinating materials like graphene has led to a worldwide surge of research initiatives for innovative applications of these and other novel two dimensional materials. Spin-orbit coupled materials such as the recently discovered topological insulators from a new class of solids that have a strong potential for novel functionalities.

 

Material-based technological innovations are more often than not initiated on the basic-science level through discoveries of new concepts, phenomena, and principles governing the physical properties of quantum materials. Research on quantum materials is a rapidly developing and internationally highly competitive interdisciplinary field. At the forefront of this field, new materials are being investigated in which relativistic spin-orbit effects and non-trivial topologies are at center stage. At the same time, materials with strong electronic correlations exhibit a wealth of non-trivial quantum ordering phenomena including superconductivity, magnetism, and other exotic orders. Precisely at the intersection of these research fields, our collaborative research center aims at exploring, understanding, developing, and utilizing quantum materials to gain deliberate control of the physical properties of these materials and to understand their dynamics, explore driven states of matter, and enable new functionalities.

 

Our diverse team of principle investigators includes scientists from experimental and theoretical physics as well as crystallography, building and expanding on the excellent research infrastructure in Cologne embedded in the Excellence Initiative key profile area 'quantum matter and materials'. The Cologne team is augmented by excellent scientists with indispensable expertise from the University of Bonn and the Forschungszentrum Jülich. Guiding philosophies of our program are the ‘materials - physical properties - theory' cycle, which is one of the cornerstones of the success of condensed-matter physics at the University of Cologne, and a multifaceted approach arising from addressing scientific topics from a variety of different perspectives as defined in the focus areas of the program.

 

The CRC will consolidate and expand Cologne together with the associated groups from Bonn and Jülich as a leading international center within quantum condensed-matter physics. Our vision is to discover, understand, and control novel collective phenomena in quantum materials arising from the interplay of spin-orbit coupling, correlations, and topology.

© Simon Wegener

TEAM OF PRINCIPAL INVESTIGATORS

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Yoichi Ando

A04 /         /


topological materials,
superconductivity,
materials synthesis,

transport measurements

Nicolae Atodiresei

C01

 

first principles simulations,

molecular nanostructures,

hybrid interfaces, molecular

electronics and spintronics

Petra Becker-Bohatý

A02

 

crystal chemistry,

structural crystallography,

crystal growth, crystal physics,

materials science

Stefan Blügel

A04 / B01 / B06

 

theory of electronic properties of real solids, spintronics,

low-dimensional systems,

spin-orbit related phenomena

B01

B06

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Markus Braden

A02 / B04

 

strongly correlated electrons, magnetism, x-ray and neutron scattering, crystallography, sample synthesis

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Jens Brede

B06

 

 

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Oliver Breunig

B01

 

 

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Ralf Bulla

C03

 

theory of condensed matter,

quantum phase transitions,

quantum impurity physics,

renormalization group methods

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Sebastian Diehl

C03 / C04

 

driven open quantum systems, topological order out of equilibrium, functional renormalization group techniques, Keldysh path integrals

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Alexander Grüneis

A01

 

2D materials: synthesis and

functionalization photoelectron spectroscopy

Raman spectroscopy

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Markus Grüninger

B02 / B03

 

exp. condensed matter physics, optical spectroscopy, strongly correlated  electron systems, spins and orbitals,

topological insulators

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Joachim Hemberger

B02

 

broadband dielectric and optical spectroscopy, frustrated magnetism,

ferroelectrics, multiferroics,

spin-ice, (quantum-)critical dynamics

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Ciarán Hickey

C06

 

 

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Achim Rosch

C02 / C04

 

condensed matter theory,

topological states, spin torques and skyrmions,

quantum phase transitions,

non-equilibrium and equilibration

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Corinna Kollath

C05

 

correlated many body systems, non-equilibrium phenomena in quantum

systems, numerical many-body physics

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Michael Scherer

C02

 

 

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Thomas Lorenz

A02 / B01

 

thermodynamics and transport, crystal growth,
frustrated quantum spin systems, spin-state transitions, multiferroics

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Alexey Taskin

A04

 

 

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Simon Trebst

C02 / C03

 

condensed matter theory,

correlated electron systems,

frustrated quantum magnets,

topological order, entanglement, numerical many-body physics

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Thomas Michely

A01 / B06

 

thin film growth kinetics and

epitaxy (oxides, metals, organics), epitaxial graphene and 2D-layers, scanning tunneling microscopy and spectroscopy

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Paul van Loosdrecht

B03 / B05

 

optically induced phenomena and non-equilibrium states of matter, steady state and time resolved advanced optical spectroscopy

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Ionela Lindfors-Vrejoiu

A01

 

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Zhe Wang

B05

 

 

FORMER PRINCIPAL INVESTIGATORS

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Maria Hermanns

C02

 

theory of condensed matter,

strongly correlated systems,

quantum spin liquids, entanglement, fractional quantum Hall effect

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Fan Yang

A04

 

exp.condensed matter physics,
topological materials,
transport measurements,
nano-device fabrication

© Simon Wegener

PROJECTS

Project Area A

Materials – preparation and characterization

A01 (Grüneis / Michely)

Spin-orbit coupling and many-body effects in novel 2D materials

 

A02 (Becker-Bohatý / Braden / Lorenz)

Crystal growth and design of materials

 

A04 (Ando / Yang)

Topological matter

Project Area B

Physical properties

© Simon Wegener

Participating institutes

 

CONTACT

Prof. Dr. Paul van Loosdrecht

II. Physikalisches Institut

Universität zu Köln

Zülpicher Str. 77

50937 Köln

Tel: +49 221 470 2707

pvl@ph2.uni-koeln.de

Speaker

Clara Berthet

II. Physikalisches Institut

Universität zu Köln

Zülpicher Str. 77

50937 Köln

Tel.: +49 221470 -2106 or -6998

berthet@ph2.uni-koeln.de

Administrative coordinator

Dr. Thomas Koethe

II. Physikalisches Institut

Universität zu Köln

Zülpicher Str. 77

50937 Köln

Tel: +49 221 470 3659

koethe@ph2.uni-koeln.de

Scientific coordinator

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