Home page
Welcome to the homepage of the group “Correlations and Topology in Condensed Matter” at the University of Melbourne led by Dr Stephan Rachel.
As condensed matter theorists, we are interested in many exciting topics ranging from strongly correlated electron systems to unconventional superconductivity and topological states of matter but also quantum computing.
If you are interested to join our group, please contact us.
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Stephan Rachel
ARC Future Fellow & Associate Professor
(Group Leader) -
Eric Mascot, PhD
McKenzie Fellow
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David Mikhail
PhD student
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Philipp Frey
PhD student
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Daniel Crawford
PhD student
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Matthew Bunney
PhD student
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Themba Hodge
PhD student
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Jacob Beyer
PhD student
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Lucca Marchetti
Master student
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Zachary Llewellyn
Master student
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Cole Peeters
Master student
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Abdul Basit
Master student
Visitors
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Dr Eric Mascot, U Illinois at Chicago (Nov – Dec 2019) -
Seydou-Samba Diop, ENS de Lyon (May – July 2019) -
Sagen Cocklin, University of Illinois at Chicago (February 2019)
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Dr Mario Fink, University of Würzburg (October 2017)
Former group members
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Benjamin Harris, MSc (Feb 2022 – Nov 2023) -
Sebastian Wolf, PhD (Oct 2017 – Aug 2021, AIP Bragg Gold Medal 2022) -
Alaric Sanders, MSc (Jan 2021 – Dec 2021) –> PhD Cambridge -
Jivan Drungilas, MSc (Jan 2019 – Dec 2020) -
Zi Chen, MSc (Jan 2019 – Dec 2020) -
Wenzhe Deng, MSc (Jan 2019 – Aug 2020) –> PhD HKUST -
Tyler Gardener, MSc (Feb 2018 – Nov 2019)
Quantum Computing and Simulation
Topics include Many-Body Quantum Entanglement, Quantum Simulators and, most importantly, Quantum Computation.
Strongly Correlated Electrons
Topics include Quantum Magnetism and Spin Liquids, Hubbard Models, Interacting Topological Insulators and Unconventional Superconductors.
Topological States of Matter
Topics include Majorana fermions and Topological Superconductors, Weyl Semimetals and Topological Insulators.
Site is under construction – more information will follow soon.
Publications
A list of publications can be found on arXiv, google scholar or Publons.
2025
- Majorana quasiparticles in atomic spin chains on superconductors
Stephan Rachel and Roland Wiesendanger
Physics Reports 1099 1, (2025).
2024
- Effect of impurities and disorder on the braiding dynamics of Majorana zero modes
Cole Peeters, Themba Hodge, Eric Mascot, Stephan Rachel
Phys. Rev. B 110, 214506 (2024), Editors’ Suggestion. - Simulating topological quantum gates intwo-dimensional magnet-superconductorhybrid structures
Jasmin Bedow, Eric Mascot, Themba Hodge, Stephan Rachel, Dirk K. Morr
npj Quantum Materials 9, 1 (2024); arXiv:2302.04889. - Fractionalized superconductivity from Majorana glue in the Kitaev-Kondo lattice
Matthew Bunney, Urban P. Seifer, Stephan Rachel, Matthias Vojta
arXiv:2411.07201. - Direct observation of dynamical quasi-condensation on a quantum computer
Philipp Frey and Stephan Rachel
arXiv:2411.02510. - Magnet-superconductor hybrid quantum systems: a materials platform for topological superconductivity
Roberto Lo Conte, Jens Wiebe, Stephan Rachel, Dirk K. Morr, Roland Wiesendanger
Invited review for La Rivista del Nuovo Cimento; arXiv:2410.20177. - Electronic structure, spin-orbit interaction and electron-phonon coupling of triangular adatom lattices on semiconductor substrates
Lucca Marchetti, Matthew Bunney, Domenico Di Sante, Stephan Rachel
arXiv:2409.17350. - Su-Schrieffer-Heeger-Hubbard model at quarter filling: effects of magnetic field and non-local interactions
David Mikhail and Stephan Rachel
Phys. Rev. B 110, 205106 (2024). - Incommensurate magnetic order: A fingerprint for electronic correlations in hole-doped cuprates
Michael Klett, Jacob Beyer, David Riegler, Jannis Seufert, Peter Wölfle, Stephan Rachel, Ronny Thomale
Phys. Rev. B 110, 085104 (2024). - Chern number landscape of spin-orbit coupled chiral superconductors
Matthew Bunney, Jacob Beyer, Ronny Thomale, Carsten Honerkamp, Stephan Rachel
Phys Rev B Letters 110, L161103 (2024). - Sublattice modulated superconductivity in the kagome Hubbard model
Tilman Schwemmer, Hendrik Hohmann, Matteo Dürrnagel, Janik Potten, Jacob Beyer, Stephan Rachel, Yi-Ming Wu, Srinivas Raghu, Tobias Müller, Werner Hanke, Ronny Thomale
Phys. Rev. B 110, 024501 (2024). - Initialization of Majorana qubits by parity-to-magnetism conversion
Dan Crawford, Roland Wiesendanger, Stephan Rachel
accepted as a Letter in Phys. Rev. B; arXiv:2404.14899. - Characterizing Dynamic Majorana Hybridization for Universal Quantum Computing
Themba Hodge, Eric Mascot, Dan Crawford, Stephan Rachel
arXiv:2403.02481. - Probing Hilbert space fragmentation and the block Inverse Participation Ratio
Philipp Frey, David Mikhail, Stephan Rachel, Lucas Hackl
Phys. Rev. B 109, 064302 (2024).
2023
- Van-Hove tuning of Fermi surface instabilities through compensated metallicity
Hendrik Hohmann, Matteo Dürrnagel, Matthew Bunney, Tilman Schwemmer, Titus Neupert, Stephan Rachel, Ronny Thomale
accepted for Phys. Rev. B; arXiv:2312.07653. - Many-body Majorana braiding without an exponential Hilbert space
Eric Mascot, Themba Hodge, Dan Crawford, Jasmin Bedow, Dirk K. Morr, Stephan Rachel
Phys. Rev. Lett. 131, 176601 (2023). - Rashba spin-orbit coupling in the square lattice Hubbard model: A truncated-unity functional renormalization group study
Jacob Beyer, Jonas Hauck, Lennart Klebl, Tilman Schwemmer, Dante M. Kennes, Ronny Thomale, Carsten Honerkamp, Stephan Rachel
Phys. Rev. B 107, 125115 (2023). - Increased localization of Majorana modes in antiferromagnetic chains on superconductors
Daniel Crawford, Eric Mascot, Makoto Shimizu, Roland Wiesendanger, Dirk K. Morr, Harald O. Jeschke, Stephan Rachel
Phys. Rev. B 107, 075410 (2023). - Detrimental effects of disorder in two-dimensional time-reversal invariant topological superconductors
Mahdi Mashkoori, Fariborz Parhizgar, Stephan Rachel, Annica M. Black-Schaffer
Phys. Rev. B 107, 014512 (2023).
2022
- Majorana modes with side features in magnet-superconductor hybrid systems
Daniel Crawford, Eric Mascot, Makoto Shimizu, Philip Beck, Jens Wiebe, Roland Wiesendanger, Harald O. Jeschke, Dirk K. Morr, Stephan Rachel
npj Quantum Mater. 7, 117 (2022). - Hilbert space fragmentation and interaction-induced localization in the extended Fermi-Hubbard model
Philipp Frey, Lucas Hackl, Stephan Rachel
Phys. Rev. B Letters 106, L220301 (2022). - Quasiparticle excitations in a one-dimensional interacting topological insulator: Application for dopant-based quantum simulation
David Mikhail, Benoit Voisin, Dominique Didier St Medar, Gilles Buchs, Sven Rogge, Stephan Rachel
Phys. Rev. B 106, 195408 (2022). - Dominant Kitaev interactions in the honeycomb materials Na3Co2SbO6 and Na2Co2TeO6
Alaric L. Sanders, Richard A. Mole, Jiatu Liu, Alex J. Brown, Dehong Yu, Chris D. Ling, Stephan Rachel
Phys. Rev. B 106, 014413 (2022). - Origin of Topological Surface Superconductivity in FeSe0.45Te0.55
Eric Mascot, Sagen Cocklin, Martin Graham, Mahdi Mashkoori, Stephan Rachel, Dirk K. Morr
Comm. Phys., 2022, 10.1038/s42005-022-00943-x - Triplet superconductivity from non-local Coulomb repulsion in Sn/Si(111)
Sebastian Wolf, Domenico Di Sante, Tilman Schwemmer, Ronny Thomale and Stephan Rachel
Phys. Rev. Lett. 128, 167002 (2022), Editors’ suggestion. - Topological superconductivity on the honeycomb lattice: Effect of normal state topology
Sebastian Wolf, Tyler Gardener, Karyn Le Hur, Stephan Rachel
Phys. Rev. B 105, L100505 (2022). - Realization of a discrete time crystal on 57 qubits of a quantum computer
Philipp Frey, Stephan Rachel
Sci. Adv. 8, eabm7652 (2022). - Competition of first-order and second-order topology on the honeycomb lattice
Matthew Bunney, Tomonari Mizoguchi, Yasuhiro Hatsugai, Stephan Rachel
Phys. Rev. B 105, 045113 (2022)
2021
- Topological Shiba bands in artificial spin chains on superconductors
Lucas Schneider, Philip Beck, Thore Posske, Daniel Crawford, Eric Mascot, Stephan Rachel, Roland Wiesendanger and Jens Wiebe
Nat. Phys. 17, 943 (2021) - From high-Tc to low-Tc: Multi-orbital effects in transition metal oxides
Michael Klett, Tilman Schwemmer, Sebastian Wolf, et int., Stephan Rachel, Ronny Thomale
Phys. Rev. B 104, L100502 (2021) - Topological Superconductivity in Skyrmion Lattices
Eric Mascot, Jasmin Bedow, Martin Graham, Stephan Rachel, Dirk K. Morr
npj Quantum Materials 6, 6 (2021)
2020
- Spin-orbit coupled superconductivity: Rashba-Hubbard model on the square lattice
Sebastian Wolf, Stephan Rachel
Phys. Rev. B 102, 174512 (2020); Editors’ suggestion. - Topological superconductivity induced by a triple-Q magnetic structure
Jasmin Bedow, Eric Mascot, Thore Posske, Götz S. Uhrig, Roland Wiesendanger, Stephan Rachel, Dirk K. Morr
Phys. Rev. B Rapid Comm. 102 180504(R) (2020) - Impurity-bound states as detectors of topological band structures revisited
Seydou-Samba Diop, Lars Fritz, Matthias Vojta, Stephan Rachel
Phys. Rev. B 101, 245132 (2020) - High-Temperature Majorana Fermions in Magnet-Superconductor Hybrid Systems
Daniel Crawford, Eric Mascot, Dirk K. Morr, Stephan Rachel
Phys. Rev. B 101, 174510 (2020) - Laser modulation of superconductivity in a cryogenic widefield nitrogen-vacancy microscope
Scott E. Lillie, David A. Broadway, Nikolai Dontschuk, Sam C. Scholten, Brett Cameron Johnson, Sebastian Wolf, Stephan Rachel, Lloyd C. L. Hollenberg, Jean-Philippe Tetienne
Nano Lett. 20 1855 (2020)
2019
- Magnon Landau levels and emergent supersymmetry in strained antiferromagnets
Mary Madelynn Nayga, Stephan Rachel, Matthias Vojta
Phys. Rev. Lett. 123, 207204 (2019) - Stability of Disordered Topological Superconducting Phases in Magnet-Superconductor Hybrid Systems
Eric Mascot, Chaitra Agrahar, Stephan Rachel, Dirk K. Morr
Phys. Rev. B 100, 235102 (2019). - Dimensional Tuning of Majorana Fermions and the Real Space Counting of the Chern Number
Eric Mascot, Sagen Cocklin, Stephan Rachel, Dirk K. Morr
Phys. Rev. B 100, 184510 (2019). - Correlation-driven charge order in a frustrated two-dimensional atom lattice
Florian Adler, Stephan Rachel, Manuel Laubach, Julian Maklar, Andrzej Fleszar, Jörg Schäfer, Ralph Claessen
Phys. Rev. Lett. 123, 086401 (2019). - Atomic-Scale Interface Engineering of Majorana Edge Modes in a 2D Magnet-Superconductor Hybrid System
Alexandra Palacio-Morales, Eric Mascot, Sagen Cocklin, Howon Kim, Stephan Rachel, Dirk K Morr, Roland Wiesendanger
Science Advances 5, eaav6600 (2019). - Quantum and Classical Phases of the Pyrochlore Heisenberg Model with Competing Interactions
Yasir Iqbal, Tobias Müller, Pratyay Ghosh, Michel J. P. Gingras, Harald O. Jeschke, Stephan Rachel, Johannes Reuther, Ronny Thomale
Phys. Rev. X 9, 011005 (2019).
2018
- Unconventional superconductivity in the extended Hubbard model: Weak-coupling renormalization group
Sebastian Wolf, Thomas L. Schmidt, Stephan Rachel
Phys. Rev. B 98, 174515 (2018), selected as an Editors’ suggestion. - Exact Excited States of Non-Integrable Models
Sanjay Moudgalya, Stephan Rachel, B. Andrei Bernevig, Nicolas Regnault
Phys. Rev. B 98, 235155 (2018). - Interacting Topological Insulators: a review
Stephan Rachel
Rep. Prog. Phys. 81, 116501 (2018). - Anisotropic susceptibilities in the honeycomb Kitaev system α-RuCl3
Paula Lampen-Kelley, Stephan Rachel, Johannes Reuther, J.-Q. Yan, Arnab Banarjee, C. A. Bridges, H. B. Cao, Steven E. Nagler, and D. Mandrus
Phys. Rev. B Rapid Comm. 98, 100403 (2018) - Pressure-tuned magnetic interactions in honeycomb Kitaev materials
Ravi Yadav, Stephan Rachel, Liviu Hozoi, Jeroen van den Brink, and George Jackeli
Phys. Rev. B Rapid Comm. 98, 121107 (2018) - Cluster-glass phase in pyrochlore XY antiferromagnets with quenched disorder
Eric C. Andrade, Jose A. Hoyos, Stephan Rachel, and Matthias Vojta
Phys. Rev. Lett. 120, 097204 (2018)
2017
- Quantized charge transport in chiral Majorana edge modes
Stephan Rachel, Eric Mascot, Sagen Cocklin, Matthias Vojta, and Dirk Morr
Phys. Rev. B 96, 205131 (2017); selected as an Editors’ suggestion. - Pseudo-Goldstone magnons in the frustrated S=3/2 Heisenberg helimagnet ZnCr2Se4 with a pyrochlore magnetic sublattice
Y. V. Tymoshenko, Y. A. Onykiienko, T. Müller, R. Thomale, S. Rachel, A. S. Cameron, P. Y. Portnichenko, D. V. Efremov, V. Tsurkan, D. L. Abernathy, J. Ollivier, A. Schneidewind, A. Piovano, V. Felea, A. Loidl, and D. S. Inosov
Phys. Rev. X 7, 041049 (2017) - Signatures of a gearwheel quantum spin liquid in a spin-1/2 pyrochlore molybdate Heisenberg antiferromagnet
Yasir Iqbal, Tobias Müller, Kira Riedl, Johannes Reuther, Stephan Rachel, Roser Valenti, Michel J. P. Gingras, Ronny Thomale, and Harald O. Jeschke
Phys. Rev. Materials 1 071201(R) (2017) - Three-band Hubbard model for Na2IrO3: Topological insulator, zigzag antiferromagnet, and Kitaev-Heisenberg material
Manuel Laubach, Johannes Reuther, Ronny Thomale, and Stephan Rachel
Phys. Rev. B Rapid Comm. 96, 121110(R) (2017); selected as an Editors’ suggestion. - Majorana Landau Level Raman Spectroscopy
Brent Perreault, Stephan Rachel, F. J. Burnell, and Johannes Knolle
Phys. Rev. B 95, 184429 (2017) - Spin freezing in the disordered pyrochlore magnet NaCaCo2F7: NMR studies and Monte-Carlo simulations
R. Sarkar, J. W. Krizan, F. Brückner, E. C. Andrade, S. Rachel, M. Vojta, R. J. Cava, and H.-H. Klauss
Phys. Rev. B 96, 235117 (2017)
Melbourne Condensed Matter Colloquium
The Melbourne Condensed Matter Colloquium (MC)^2 is jointly organised by the University of Melbourne and the Royal Melbourne Institute of Technology (RMIT). All interested experimentalists and theorists from the Melbourne area are invited. For questions please contact Stephan Rachel, Jared Cole or Andy Martin.
Thanks to the joint effort of researchers of La Trobe University, Swinburne University of Technology, Monash University, RMIT and University of Melbourne, we have recently launched the semi-annual workshop series “Melbourne Condensed Matter Community (MC)^2”.
Here you find a list of announced and previous events:
2021:
- 19/07/21 Dr Ria R Joseph (Swinburne)
- 31/05/21 –> 5th (MC)^2 workshop @ Melbourne –> postponed
- 03/05/21 Prof Frank Pollmann (TU Munich)
2020:
- 02/03/20 Prof Oleg Sushkov (UNSW)
2019:
- 01/11/19 –> 4th (MC)^2 workshop @ Melbourne
- 21/10/19 Dr Andrew Martin (RMIT)
- 30/07/19 Dr Dmitry Efimkin (Monash)
- 24/06/19 Dr Mark Edmonds (Monash) / Dr Stephan Rachel (Melbourne)
- 07/06/19 –> 3rd (MC)^2 workshop @ RMIT
- 06/05/19 A/Prof Jeffrey Davis (Swinburne) at 15:00
- 29/04/19 A/Prof Rajib Rahman (UNSW) @ RMIT
- 25/03/19 Prof Susan Coppersmith (UNSW)
- 18/02/19 Prof Sven Rogge (UNSW)
2018:
- 19/11/18 Dr Vladimir A Yurovski (Tel Aviv University, Israel)
- 16/11/18 –> 2nd (MC)^2 workshop @ Monash
- 29/10/18 Dr Vudtiwat Ngampruetikorn (Northwestern, USA)
- 08/10/18 Dr Tapio Simula (Monash)
- 03/09/18 A/Prof Andy Martin (U Melbourne)
- 30/07/18 A/Prof Lan Wang (RMIT)
- 25/06/18 Dr James Quach (ICFO, Barcelona, Spain)
- 08/06/18 –> 1st (MC)^2 workshop @ Swinburne
- 04/06/18 Prof Ben Powell (U Queensland)
- 07/05/18 Dr Julie Karel (Monash)
- 16/04/18 Dr Agustin Schiffrin (Monash)
- 05/03/18 Prof Jared Cole (RMIT)
Talks are scheduled for 4.30pm if not announced otherwise.