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Fabrication and Characterization of Superconducting Resonators
Published on: May 21, 2016
Circular polarization in a non-magnetic resonant tunneling device
Lara F Dos Santos1, Yara Galvão Gobato, Márcio D Teodoro
1Physics Department, Federal University of São Carlos, São Carlos, Brazil. yara@df.ufscar.br.
Nanoscale Research Letters
|June 30, 2011
Summary
We studied spin polarization in a GaAs/AlAs/GaAlAs resonant tunneling diode using photoluminescence. Strong circular polarization was observed, influenced by electron and hole gases in contact layers and quantum confinement effects.
Area of Science:
- Semiconductor physics
- Quantum phenomena
- Optoelectronics
Background:
- Resonant tunneling diodes (RTDs) are crucial for high-frequency electronics.
- Understanding spin polarization in quantum wells (QWs) is key for spintronics.
- GaAs/AlAs heterostructures provide a tunable platform for quantum studies.
Purpose of the Study:
- To investigate polarization-resolved photoluminescence (PL) in an n-type GaAs/AlAs/GaAlAs RTD.
- To analyze the influence of magnetic fields on spin polarization within the QW.
- To identify factors affecting circular polarization in the QW.
Main Methods:
- Polarization-resolved photoluminescence (PL) spectroscopy.
- Application of a magnetic field parallel to the tunnel current (up to 19 T).
- Analysis of optical emission from quantum well and contact layers.
Main Results:
- Strong circular polarization observed in the quantum well PL (up to -70% at 19 T).
- Evidence of spin-polarized 2D electron and hole gases in GaAs contact layers.
- Observed spin polarization in contact layers influences QW carrier spin polarization.
Conclusions:
- Circular polarization in the QW is strongly dependent on external magnetic fields.
- Carrier spin polarization is affected by 2D electron and hole gases in contact layers.
- QW polarization degree is modulated by g-factors, carrier densities, and Zeeman and Rashba effects.
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