Related Experiment Video
Updated: Jun 4, 2026
10:26
Fabrication and Characterization of Superconducting Resonators
Published on: May 21, 2016
Interference of Fano-Rashba conductance dips
M M Gelabert1, A Renart, L Serra
1Departament de Física, Universitat de les Illes Balears, Palma de Mallorca, Spain.
Summary
Interference in quantum wires with two Rashba regions shows distinct transmission behaviors. Depending on separation, Fano-Rashba dips cross or anti-cross, revealing Fabry-Perot oscillations or enhanced transmission from evanescent modes.
Area of Science:
- Condensed matter physics
- Quantum mechanics
- Mesoscopic physics
Background:
- Quantum wires support single propagating modes.
- Tunable Rashba spin-orbit interaction influences electron transport.
- Interference phenomena are crucial in nanoscale devices.
Purpose of the Study:
- Investigate the interference effects of two tunable Rashba regions in a quantum wire.
- Analyze how the distance between regions affects transmission properties.
- Explore the role of evanescent modes at short separations.
Main Methods:
- Utilized scattering matrix theory for analytical expressions.
- Modeled a quantum wire with one propagating mode.
- Simulated interference patterns based on region separation.
Main Results:
- Observed transmission dips (Fano-Rashba dips) that either cross or anti-cross.
- Identified Fabry-Perot oscillations at large separations due to mode interference.
- Found enhanced transmission and destruction of conductance dips at small separations due to overlapping evanescent modes.
Conclusions:
- The spatial separation of tunable Rashba regions dictates interference outcomes.
- Evanescent mode overlap significantly alters quantum transport at short distances.
- Understanding these interference effects is vital for designing quantum devices.
Related Concept Videos
01:22Biasing of FET
Biasing a Junction Field Effect Transistor (JFET) is crucial for setting operational parameters and ensuring efficient functioning in electronic circuits. JFETs are characterized by using a single carrier type in N-channel or P-channel configurations, where the channel is surrounded by PN junctions. These junctions are central to the device's ability to control current flow.
In an N-channel JFET, the structure consists of N-type material forming the channel on a P-type substrate, with the gate...
In an N-channel JFET, the structure consists of N-type material forming the channel on a P-type substrate, with the gate...
01:27Biasing of Metal-Semiconductor Junctions
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
02:18Interference and Diffraction
Interference is a characteristic phenomenon exhibited by waves. When two electromagnetic waves interact with their peaks and troughs coinciding, a resulting wave with enhanced amplitude is produced. This is known as constructive interference. In this case, the two waves interacting are in phase with each other.
01:24Metal-Semiconductor Junctions
The contact of metal and semiconductor can lead to the formation of a junction with either Schottky or Ohmic behavior.
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The semiconductor's...
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The semiconductor's...
01:16Biasing of P-N Junction
The operation of a p-n junction diode involves various biasing conditions, including forward bias, reverse bias, and equilibrium.
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
In equilibrium, no external voltage is applied across the p-n junction. The depletion region is formed at the junction interface due to the diffusion of carriers, which leaves behind charged dopants, acceptors on the p-side, and donors on the n-side. These immobile charges create an electric field that prevents further diffusion of carriers. The related energy band...
01:07Interference and Superposition of Waves
When two waves of the same nature occur in the same region simultaneously, they result in interference. Interference of waves implies that the net effect of the waves is the sum of the individual waves' effects. However, it does not imply that the individual waves affect the propagation of other waves.
Interference occurs in mechanical waves, such as sound waves, waves on a string, and surface water waves. Mechanical waves correspond to the physical displacement of particles. Hence,...
Interference occurs in mechanical waves, such as sound waves, waves on a string, and surface water waves. Mechanical waves correspond to the physical displacement of particles. Hence,...