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Evidence of soft-mode quantum phase transitions in electron double layers
1V. Pellegrini, Bell Laboratories, Lucent Technologies, Murray Hill, NJ 07974, USA, and Scuola Normale Superiore and Istituto Nazionale per la Fisica della Materia, Pisa, Italy. A. Pinczuk, Bell Laboratories, Lucent Technologies, Murray Hill.
Science (New York, N.Y.)
|August 7, 1998
Summary
Inelastic light scattering identified three electron spin configurations in gallium arsenide quantum wells. These spin states transform via quantum phase transitions, linked to collective excitations.
Area of Science:
- Condensed Matter Physics
- Quantum Materials
- Two-Dimensional Electron Systems
Background:
- Electron double layers in gallium arsenide quantum wells exhibit complex spin behaviors.
- Even-integer quantum Hall states are crucial for understanding electron correlations.
Purpose of the Study:
- To investigate the spin configurations and their transitions in electron double layers.
- To explore the relationship between quantum phase transitions and collective excitations.
Main Methods:
- Utilizing inelastic light scattering to probe low-energy spin excitations.
- Analyzing electron spin dynamics in gallium arsenide quantum wells.
Main Results:
- Observed three distinct electron spin configurations at even-integer quantum Hall states.
- Identified quantum phase transitions driven by Coulomb interactions and Zeeman splittings.
- Correlated a spin-state transformation with a vanishingly low-energy spin-flip excitation.
Conclusions:
- Quantum phase transitions are linked to soft collective excitations in two-dimensional electron systems.
- Provides direct evidence for the interplay between spin configurations and excitations.
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