Regensburg 2025 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 43: Correlated Electrons: Other Theoretical Topics
TT 43.2: Talk
Thursday, March 20, 2025, 09:45–10:00, H33
Inducing strong electronic correlation by charged impurities in weakly interacting two-dimensional electron system — Junho Bang1, Byeongin Lee1, João Augusto Sobral2, Sayan Banerjee2, Mathias Scheurer2, •Jianfeng Ge3, and Doohee Cho1 — 1Department of Physics, Yonsei University, Seoul 03722, Korea — 2Institute for Theoretical Physics III, University of Stuttgart, 70550 Stuttgart, Germany — 3Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
When translational invariance is broken, e.g. in the presence of impurities, an ordered state can emerge where the electronic charge density modulates spatially. While conventional charge modulations are explained by weak-impurity scattering of Landau quasiparticles, strong correlations may drive the electrons to depart from the Fermi liquid behavior. Using scanning tunneling microscopy and spectroscopy, we switch the ionization state of individual surface impurities and discover a local phase transition induced by the impurity potential. A nanoscale charge-ordered phase, which breaks the symmetry of the underneath hosting lattice, spontaneously emerges from the otherwise uniform two-dimensional electron system. Further, the charge modulations appear with an anisotropy distinct from that of the Fermi surface, excluding any Fermi-surface-related interpretations for the ordered phase. While the exact origin of the solid-like electronic phase remains a mystery, our work demonstrates a microscopic approach for creating and manipulating strongly correlated electrons in two-dimensional systems even with weak intrinsic interactions.
Keywords: correlated electrons; charge order; scanning tunneling microscopy; phase transition; impurity