Emergent phenomena in topological quantum materials

Topic 9
Main supervisor Y.Su (y.su@fz-juelich.de)
MLZ institution FZJ
Local supervisor 1 R.Mezei
Institution Mirrotron
Local supervisor 2 P.Boeni
Institution Swiss Neutronics
Local supervisor 3 M.Gehring
Institution Bilfinger Noell
Local supervisor 4
Title Emergent phenomena in topological quantum materials

Recent theoretical predictions and experimental realizations of exotic quasi-particles and topological excitations in condensed matter have led to tremendous research interests in topological quantum materials. For instance, correlated topological materials, such as e.g. magnetic Dirac and Weyl semimetals, and intrinsic magnetic topological insulators, in which both non-trivial topology of single-electron band structures and electron-electron correlations are essential ingredients, have emerged as an exciting platform to explore novel electronic and magnetic phenomena. Meanwhile, frustrated quantum magnets have become the promising candidate materials for the experimental realization of the enigmatic quantum spin liquid state, in which fractionalized excitations, topological order and non-local quantum entanglement can be an ideal playground for future quantum technologies. As a unique microscopic probe for magnetic structures and excitations, neutron scattering matches the entire range of length and time scales relevant to those novel quantum phenomena, and is therefore ideally suited for studying topological quantum materials. This can be demonstrated by the recent work [1-7] carried out in the group led by the main supervisor at MLZ. The central focus of the proposed GNeuS project is to carry out neutron scattering studies of exotic order and emergent excitations in topological quantum materials, with the aim to elucidate the intricate interplay between topology, correlation and frustration. Given the recently commissioned time-of-flight inelastic neutron scattering (TOF-INS) option at the polarized instrument DNS [8], a particular focus of this project is to fully exploit the tremendous potential by combining TOF-INS and wide-angle polarization analysis, and to be actively involved in the further instrumentation developments. To model the inelastic and polarized diffuse neutron scattering data using advanced numerical approaches in a close collaboration with the leading theory groups could also form an essential part of this project. High-quality single crystals of various topological quantum materials, including Kitaev material a-RuCl3, pyrochlore spin ice, 2D van der Waals ferromagnets, and topological kagome metals have been successfully grown in the group, which can be ideally used for this project. The candidates are also encouraged to carry out sample synthesis of emergent quantum materials by using our in-house laboratory.


[1] V. Pecanha-Antonio, et al., Phys. Rev. B 96, 214415 (2017)

[2] V. Pecanha-Antonio, et al. Phys. Rev. B 99, 134415 (2019)

[3] F. Zhu, et al., Phys. Rev. Research 2, 043100 (2020)

[4] F. Zhu, et al., Sci. Adv. 7, eabi7532 (2021)

[5] L.C. Zhang, et al., Phys. Rev. B 103, 134414 (2021)

[6] X. Mi, et al., Phys. Rev. B 103, 174413 (2021)

[7] K.X. Zhang, et al., ACS Appl. Mater. Interfaces 13, 20788 (2021)

[8] Ivica Živković, et al., Phys. Rev. Lett. 127, 157204 (2021).