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Updated: May 30, 2026
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All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
Density functional study of collective electron localization: detection by persistent current
Marc Siegmund1, Markus Hofmann, Oleg Pankratov
1Lehrstuhl für Theoretische Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstrasse 7 B2, D-91058 Erlangen, Germany.
Summary
The study reveals that persistent current in quantum rings signals Wigner crystal formation when electron-electron interactions exceed a threshold. This macroscopic current indicates the emergence of correlated electron states, crucial for understanding condensed matter systems.
Area of Science:
- Condensed Matter Physics
- Quantum Chemistry
- Computational Physics
Background:
- Persistent currents in quantum systems are sensitive to electron-electron interactions and external potentials.
- Symmetry breaking can alter the relationship between current and interaction strength.
- Density Functional Theory (DFT) provides a framework for studying correlated electron systems.
Purpose of the Study:
- To investigate the impact of electron-electron interactions on persistent currents in a quantum ring model.
- To determine the threshold for correlated electron state formation using DFT.
- To establish macroscopic current as an indicator of Wigner crystal formation.
Main Methods:
- Application of the optimized effective potential (OEP) implementation of DFT.
- Modeling interacting spinless electrons on a quantum ring with a magnetic flux.
- Inclusion of a weak Gaussian-shaped impurity potential to break rotational symmetry.
Main Results:
- Persistent current remains constant for weak electron-electron interactions (r(S) < 2.05).
- Current decays exponentially above a critical interaction strength (r(S) ≈ 2.05), indicating Wigner crystal formation.
- Electron density exhibits periodic modulation above the threshold, characteristic of a second-order phase transition.
Conclusions:
- Macroscopic persistent current serves as a direct indicator of correlated electron state formation in DFT.
- The DFT-OEP approach accurately captures the transition to an electron Wigner crystal.
- Understanding these transitions is vital for designing novel electronic materials and devices.
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