Attosecond clocking of correlations between Bloch electrons.
J Freudenstein1, M Borsch2, M Meierhofer1
1Department of Physics, University of Regensburg, Regensburg, Germany.
Nature
|October 12, 2022
Summary
Researchers developed attosecond chronoscopy to observe electron motion in solids. Strong correlations in WSe2 shifted electron recollision timing, offering new insights into quantum dynamics and phase transitions.
Area of Science:
- Solid-state physics
- Quantum mechanics
- Attosecond science
Background:
- Delocalized Bloch electrons and their correlations govern solid-state properties like optical and electronic functionalities.
- Previous attosecond probing lacked energy resolution to study millielectronvolt-scale electron interactions near the Fermi energy.
- Subfemtosecond temporal precision is needed to directly observe many-body correlations influencing electron motion.
Purpose of the Study:
- To develop a method for directly capturing how many-body correlations affect Bloch electron motion with subfemtosecond precision.
- To investigate the influence of strong Coulomb correlations on electron-hole pair dynamics in crystalline semiconductors.
- To provide a quantitative understanding of electron dynamics influenced by Coulomb interactions, non-classical aspects, driving fields, and valley polarization.
Main Methods:
- Utilizing multi-terahertz light fields to drive electron-hole pairs in semiconductors onto closed trajectories.
- Employing attosecond chronoscopy with 300 attosecond precision to measure the delay between electron-hole pair separation and recollision.
- Performing quantitative analysis with quantum-dynamic many-body computations in a Wigner-function representation.
Main Results:
- Achieved 300 attosecond temporal precision, resolving 0.7% of the driving field's oscillation period.
- Observed that strong Coulomb correlations in atomically thin WSe2 shift optimal recollision timing by 1.2 ± 0.3 femtoseconds compared to bulk material.
- Gained an intuitive view of how Coulomb interaction, non-classical effects, driving field strength, and valley polarization impact electron dynamics.
Conclusions:
- Attosecond chronoscopy provides unprecedented insight into the dynamics of delocalized electrons and many-body correlations.
- The findings reveal the significant role of Coulomb correlations in dictating electron motion and timing in semiconductors.
- This technique has the potential to revolutionize the understanding of phase transitions and quantum phenomena for future technologies.
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