Atomic-scale imaging of a static and dynamic ordered electronic state pinned by lattice defects

• Applicant: Dr. Michael Kinyanjui
• Subject Area: Experimental Condensed Matter Physics ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 452020359

• Final Report Year: 2024

Final Report Abstract

Interaction of ordered phenomena with lattice disorder has profound effect on the structural, transport, and magnetic properties of many quantum materials. Some of these phenomena include charge-density waves (CDW), magnetic Skyrmion lattices, vortices in superconductors among others. In materials with co-existing superconducting and CDW phases, pinning of static and dynamic CDW by lattice disorder has been shown to lead to suppression of the CDW phase enhancing superconductivity. This has prompted interest in designing atomicscale pinning landscapes to tune electronic phases. This however requires a better atomicscale understanding of the pinning interactions. This need is increasingly met by experimental advances in real-space imaging and spectroscopic methods sensitive to various ordered electronic phases, underlying atomic lattice as well as disorder. The goal of the project was therefore to understand how an electronic ground state in form of charge density waves, an electronic phase characterized by superstructure of electron density, responds to lattice defects and disorder at the atomic scale. Results show that the CDW electronic phase responds with an elastic-like strain response to the lattice defects and deformations induced in the underlying atomic lattice. This is characterized by phase defects in the CDW electronic phase including dislocations and domain walls, CDW strain as well as CDW disorder. The project results show the role of externally induced lattice deformations and defects in modulating or disordering electronic phases in at the atomic scale in 2D quantum materials.

Publications

• “Imaging the atomic -scale effects of controlled disorder on an ordered electronic state in 2d quantum materials,” in Proceedings of the European conference on Chemistry of Two-dimensional materials, Bologna chem2Dmat, Bologna, Italy, 31 Aug
  M. Kinyanjui & T. Matsuura
  
• Atomic-scale mapping of pressure-induced deformations and phase defects in the charge density wave order parameter. Physical Review B, 104(12).
  Kinyanjui, M. K.; Ebad-Allah, J.; Krottenmüller, M. & Kuntscher, C. A.
  
• Pressure on Triethylenediamine–TaS2 Intercalation Complex: Effects on Charge Density Wave Modulation and Molecular Structure. The Journal of Physical Chemistry C, 126(45), 19346-19354.
  Kinyanjui, Michael K.; Holzbock, Jürgen; Linden, Mika; Ebad-Allah, Jihaan; Krottenmüller, Markus & Kuntscher, Christine A.
  
• “Ordered electronic states in 2d quantum materials: Imaging effects of hydrostatic pressure at the atomic scale,” in Proceedings of the 16th Multinational Congress on Microscopy 16MCM, Brno, Czech Republic, Sept. 4 - 9, 2022.
  M. Kinyanjui, J. Ebad-Allah, M. Krottenmueller & C. Kuntscher
  
• Electron-Beam- and Thermal-Annealing-Induced Structural Transformations in Few-Layer MnPS3. ACS Nano, 17(5), 4250-4260.
  Storm, Alexander; Köster, Janis; Ghorbani-Asl, Mahdi; Kretschmer, Silvan; Gorelik, Tatiana E.; Kinyanjui, Michael Kiarie; Krasheninnikov, Arkady V. & Kaiser, Ute
  
• “How do atomic-scale lattice defects modulate ordered electronic phases in 2d quantum materials?” In Proceedings of the Defects in Two-dimensional Materials, 750. WE-Heraeus-Seminar, Bad Honnef, Germany, May 08 - 12 2023.
  M. Kinyanjui, J. Holzbock, M. Linden, J. Ebad-Allah, M. Krottenmueller & C. Kuntscher
  
• “Modulation of nearand mid-infrared surface plasmons by electronic phase defects in the charge density wave metal T bTe3,” in Proceedings of the 20th International Microscopy Conference, Busan, South Korea, Sept. 10-15, 2023.
  M. Kinyanjui, B. Haas, P. M. Monceau, H.-P. Komsa & C. Koch
  
• “Modulation of nearand mid-infrared surface plasmons by electronic phase defects in the charge density wave metal T bTe3,” in Proceedings of the Nanophotonics and Micro/Nano Optics International Conference 2023, Barcelona, Spain, Nov 27-29 2023.
  M. Kinyanjui, B. Haas, P. M. Monceau, H.-P. Komsa & C. Koch
  
• “Ordered electronic states in 2d quantum materials: Imaging effects of hydrostatic pressure at the atomic scale,” in Proceedings of the 16th Multinational Congress on Microscopy 16MCM, Darmstadt, Germany, Feb. 26 - 2 Mar. 2023.
  M. Kinyanjui, J. Ebad-Allah, M. Krottenmueller & C. Kuntscher
  
• Phase transformations in single-layer MoTe2 stimulated by electron irradiation and annealing. Nanotechnology, 35(14), 145301.
  Köster, Janis; Kretschmer, Silvan; Storm, Alexander; Rasper, Fabian; Kinyanjui, Michael K.; Krasheninnikov, Arkady V. & Kaiser, Ute