Thermally enhanced Wigner oscillations in two-electron 1D quantum dots

Area of Science:

• Condensed Matter Physics
• Quantum Mechanics
• Mesoscopic Physics

Background:

• Two-electron quantum dots exhibit complex behavior influenced by electron-electron interactions.
• Friedel oscillations and Wigner molecule states describe electron density distributions at zero temperature.
• Understanding thermal stability is crucial for quantum dot applications.

Purpose of the Study:

• Investigate the thermal stability of electron density fluctuations in a 1D quantum dot.
• Analyze the interplay between Friedel and Wigner correlations under varying temperatures.
• Explain the peculiar thermal enhancement of Wigner correlations in intermediate interaction regimes.

Main Methods:

• Exact diagonalization of the two-electron system.
• Computation of finite-temperature average electron density.
• Analysis of characteristic temperature scales (T(F) and T(W)).

Main Results:

• At zero temperature, weak interactions show Friedel oscillations, while strong interactions form Wigner molecules.
• Increasing temperature smears Friedel oscillations and melts Wigner molecules.
• A novel thermal enhancement of Wigner correlations is observed in the intermediate interaction regime.
• This enhancement occurs when T(F) < T(W), making Wigner oscillations more visible.

Conclusions:

• The study identifies two distinct temperature scales governing Friedel and Wigner oscillations.
• The findings explain the enhanced visibility of Wigner correlations at intermediate interactions due to T(F) < T(W).
• Results complement existing theories, such as the Luttinger liquid picture for larger particle systems.