Autumn School on Correlated Electrons:
Orbital Physics in Correlated Matter

18-22 September 2023, Forschungszentrum Jülich

Announcement: Poster and Flyer


In a classic paper 50 years ago, Kugel and Khomskii demonstrated that in strongly-correlated systems orbital ordering can arise from a purely electronic super-exchange mechanism and not just the conventional co-operative Jahn-Teller effect. This work opened the field of orbital physics — a field which, since then, is undergoing continuous growth. It was understood that, beside orbital ordering, super-exchange can give rise to the orbital analogue of spin-liquid states. It was shown that the directional character of the orbitals can introduce anisotropic super-exchange interactions, which, in a simplified setting, are described by compass models, a prototype for the Kitaev model. This opened new avenues of its own. More surprising phenomena arise from the entanglement of spin and orbital degrees of freedom. New developments aim at dynamically tuning orbital occupations by pushing the system out of equilibrium, and at orbital-controlled electronics.

The goal of this year’s school is to provide students with an overview of the state-of-the art in the field of orbital physics in strongly correlated systems and the techniques used to investigate them. After introducing fundamental models and effects, lectures will focus on these effects in real materials, with introductions to crystallography and symmetries, methods for building minimal tight-binding Hamiltonians, the Jahn-Teller effect, and Coulomb-enhancements of the Jahn-Teller effect. Advanced lectures will address orbital ordering, orbital liquids and Kitaev materials, as well as theoretical approaches, from self-interaction corrected density functionals to dynamical mean-field theory and beyond. Experimental lectures will present probes of spin, orbital, and charge degrees of freedom, techniques to image orbitals and orbital ordering, as well as orbitally-controlled transport phenomena.

group photo
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Click on the lecture for the slides.

  Mon 18 Sept Tue 19 Sept Wed 20 Sept Thu 21 Sept Fri 22 Sept
09:00 Welcome Exchange Mechanisms
E. Koch
Probing Spin, Charge, Orbital
E. Benckiser
R. Eder
Coupled Cluster
A. Grüneis
10:30Coffee Break
11:00 Orbital Ordering
E. Pavarini
Photo Oxide Interfaces
J. Chakhalian
Kitaev Magnets
A. Lichtenstein
14:00 Jahn-Teller
A. Ceulemans
Spin-Orbital Entanglement
A. Oleś
f-electron systems
B. Amadon
Orbital Peierls
T. Mizokawa
Bus to Aachen
15:30Coffee Break
16:00 Imaging Orbitals
H. Tjeng
Quantum Criticality
M. Vojta
N. Lanatà
Self-Interaction Correction
M. Pederson
18:00 Bus to Aachen Poster Session
Bus to Aachen
21:00 Bus to Aachen

General Information

Venue: The school will take place from 18-22 September 2023 at the Forschungszentrum Jülich, in the Lecture Hall of the Peter-Grünberg Institute, building 4.8, room 365.

Participation: The school is intended for advanced graduate or PhD students and postdocs in the field of electronic structure of materials.

Admission: Interested students should apply before May 31, 2023 through the registration form. Accepted applicants will be informed via e-mail two weeks after the deadline for applications.

Accommodation: Students can apply for financial support to cover accommodation costs. Participants supported by the school will be accommodated in the Aachen Youth Hostel. Funding for accommodations is limited.

ICAM Junior Travel Awards: Eligible candidates can apply for an ICAM Junior Travel Award. Funding is limited to about 10 students. For more information see the ICAM site and the registration form.

Transport: A shuttle bus will be operating in the mornings and evenings between the Youth Hostel in Aachen and the Forschungszentrum Jülich. The bus will leave in the morning from Aachen Jugendherberge. There will also be a shuttle from Jülich, from Stadthotel Jülich.
Other ways to reach the Forschungszentrum.

Hotels in Aachen and Jülich: Participants for whom no low-cost accommodation can be found or who wish to stay in a hotel may find hotels at these web-sites: Jülich and Aachen.

Lecture Notes

book cover The lecture notes have been published as an OpenAccess book:

Eva Pavarini and Erik Koch (eds.)
Orbital Physics in Correlated Matter
Modeling and Simulation, Vol. 13
Verlag des Forschungszentrum Jülich, 2023
ISBN 978-3-95806-689-2


Autumn School on Correlated Electrons

Overview of the Schools in the Series

The School is supported by

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