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Simon Elliot Wall


Keywords

  • Condensed matter physics
  • Quantum and nanoscale materials
  • Structural dynamics
  • Light induced phase transitions
  • X-ray lasers
  • Synchrotron radiation
  • Symmetry

Head of the Ultrafast Dynamics of Quantum Materials group

Associate Professor

PhD in Physics

Optically controlling quantum materials.

Quantum materials exhibit fascinating and desirable properties, such as high temperature superconductivity, but are challenging to understand. They are complex systems in which multiple degrees of freedom compete to dictate the material’s properties These interactions both make it difficult to understand what drives the emergence of specific properties, but also opens new routes to control their properties.

Our research group exploits the entire electromagnetic spectrum, from THz radiation up to hard X-rays to manipulate and measure the properties of quantum materials. We are particularly interested in how lights can perturb and induce symmetry changes in quantum materials, and how these can be used to manipulate the properties of quantum materials. We do this with a range of lab-based ultrafast optical methods to track materials on timescale of a few femtoseconds and in addition, we exploit newly emerging X-ray lasers to capture atomic and nanoscopic changes in materials with light.

Recent publications

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Tanikawa, T., Karabekyan, S., Kovalev, S., Casalbuoni, S., Asgekar, V., Bonetti, S., Wall, S., Laarmann, T., Turchinovich, D., Zalden, P., Kampfrath, T., Fisher, A. S., Stojanovic, N., Gensch, M. & Geloni, G. (2020). Volt-per-Ångstrom terahertz fields from X-ray free-electron lasers. Journal of Synchrotron Radiation, 27, 796-798. https://doi.org/10.1107/S1600577520004245
Johnson, A. S., Perez-Salinas, D., Siddiqui, K. M., Kim, S., Choi, S., Volckaert, K., Majchrzak, P. E., Ulstrup, S., Agarwal, N., Hallman, K., Haglund, R. F., Günther, C. M., Pfau, B., Eisebitt, S., Backes, D., Maccherozzi, F., Fitzpatrick, A., Dhesi, S. S., Gargiani, P. ... Wall, S. E. (2023). Ultrafast X-ray imaging of the light-induced phase transition in VO2. Nature Physics, 19(2), 215-220. https://doi.org/10.1038/s41567-022-01848-w
Johnson, A. S., Pérez-Salinas, D., Siddiqui, K. M., Choi, S., Volckaert, K., Majchrzak, P. E., Ulstrup, S., Hallman, K., Haglund, R. F., Günther, C. M., Pfau, B., Eisebitt, S., Backes, D., Maccherozzi, F., Fitzpatrick, A., Dhesi, S., Gargiani, P., Valvidares, M., Choi, H. ... Wall, S. E. (2022). Ultrafast X-Ray hyperspectral imaging of the photo-induced phase transition in VO2. In International Conference on Ultrafast Phenomena, UP 2022 Article Tu3A.2 Optica Publishing Group (formerly OSA). https://doi.org/10.1364/UP.2022.Tu3A.2
Monti, M., Siddiqui, K. M., Perez-Salinas, D., Agarwal, N., Bremholm, M., Li, X., Prabhakaran, D., Liu, X., Babich, D., Sander, M., Deng, Y., Lemke, H. T., Mankowsky, R., Liu, X. & Wall, S. E. (2026). Ultrafast surface melting of orbital order in La0.5Sr1.5MnO4. Nature Materials, 25(1), 58-64. https://doi.org/10.1038/s41563-025-02379-4
Johnson, A. S., Moreno-Mencía, D., Amuah, E. B., Menghini, M., Locquet, J. P., Giannetti, C., Pastor, E. & Wall, S. E. (2022). Ultrafast Loss of Lattice Coherence in the Light-Induced Structural Phase Transition of V2O3. Physical Review Letters, 129(25), Article 255701. https://doi.org/10.1103/PhysRevLett.129.255701