Photovoltaic effects in GaAs/AlGaAs quantum Hall devices by optical vortex irradiation

Area of Science:

• Condensed Matter Physics
• Quantum Optics
• Semiconductor Physics

Background:

• Quantum Hall effect in two-dimensional electron systems (2DES) exhibits unique transport properties due to edge states.
• Optical vortices possess orbital angular momentum, enabling novel light-matter interactions.

Purpose of the Study:

• To investigate the photovoltaic effects induced by optical vortex irradiation in a GaAs/AlGaAs 2DES under quantum Hall conditions.
• To explore the dependence of the photovoltaic response on the topological charge (m) of optical vortices.

Main Methods:

• Utilizing a GaAs/AlGaAs heterostructure subjected to high magnetic fields and cryogenic temperatures.
• Irradiating the 2DES with perfect optical vortices of varying topological charges (m = ±1, ±2, ±3, ±4).
• Measuring the resulting photovoltage and photocurrent to analyze the photovoltaic effect.

Main Results:

• A distinct difference in photovoltaic response was observed between optical vortices with odd (m = ±1, ±3) and even (m = ±2, ±4) topological charges.
• The parity of the topological charge influences photoexcitation and/or electron transport in the edge states.
• Photocurrent dependence on topological charge is attributed to eddy currents from interband electron excitation.

Conclusions:

• The parity of the topological charge of optical vortices plays a crucial role in photovoltaic effects within quantum Hall 2DES.
• This finding offers insights into controlling light-induced charge transport in topological electronic systems.
• The study highlights the potential of optical vortices for manipulating electron dynamics in quantum systems.