Related Experiment Video
Updated: Jun 17, 2025
10:54
Dissolution Dynamic Nuclear Polarization Instrumentation for Real-time Enzymatic Reaction Rate Measurements by NMR
Published on: February 23, 2016
10.6K
Spin Polarization via Adiabatic and Counterdiabatic Engineering
1School of Physics, <a href="https://ror.org/03r8z3t63">University of New South Wales</a>, Sydney 2052, Australia.
Physical Review Letters
|August 9, 2024
Summary
Researchers engineered quantum point contacts to function as spin filters, enabling control over electron spin states. This breakthrough allows for the creation of spin-polarized beams with robust and practical applications.
Area of Science:
- Quantum physics
- Condensed matter physics
- Spintronics
Background:
- A spin filter allows only a single electron spin state to pass, analogous to polarizing filters for light.
- Quantum point contacts are nanoscale electronic devices with tunable properties.
Purpose of the Study:
- To demonstrate that the potential landscape of a quantum point contact can be engineered to act as a spin filter.
- To show that these engineered quantum point contacts can generate a spin-polarized beam.
- To confirm the robustness of this effect in practical experimental settings.
Main Methods:
- Utilizing principles of shortcuts to adiabaticity to tune the potential landscape.
- Experimentally investigating asymmetrically biased quantum point contacts in Indium Arsenide (InAs) quantum wells.
Main Results:
- Successfully demonstrated the potential landscape tuning of quantum point contacts to function as two-terminal spin filters.
- Generated a spin-polarized electron beam using the engineered quantum point contacts.
- Confirmed that even rough engineering of the quantum point contact yields a significant spin-filtering effect.
Conclusions:
- The potential landscape of quantum point contacts can be effectively manipulated to create robust spin filters.
- This method offers a practical approach to generating spin-polarized beams for spintronic applications.
- Experimental validation in InAs quantum wells confirms the feasibility and robustness of the proposed spin-filtering mechanism.
Related Concept Videos
01:20Work Done in an Adiabatic Process
3.1K
Consider the adiabatic compression of an ideal gas in the cylinder of an automobile diesel engine. The gasoline vapor is injected into the cylinder of an automobile engine when the piston is in its expanded position. The temperature, pressure, and volume of the resulting gas-air mixture are 20 °C, 1.00 x 105 N/m2, and 240 cm3 , respectively. The mixture is then compressed adiabatically to a volume of 40 cm3. Note that, in the actual operation of an automobile engine, the compression is not...
3.1K
01:18Adiabatic Processes for an Ideal Gas
3.1K
When an ideal gas is compressed adiabatically, that is, without adding heat, work is done on it, and its temperature increases. In an adiabatic expansion, the gas does work, and its temperature drops. Adiabatic compressions actually occur in the cylinders of a car, where the compressions of the gas-air mixture take place so quickly that there is no time for the mixture to exchange heat with its environment. Nevertheless, because work is done on the mixture during the compression, its...
3.1K
01:27Pressure and Volume in an Adiabatic Process
2.7K
Free expansion of a gas is an adiabatic process. However, there are few differences between free expansion and adiabatic expansion. During free expansion, no work is done, and there is no change in internal energy. But, for an adiabatic expansion, work is done, and there is a change in internal energy. During an adiabatic process, the relation between the pressure and volume is obtained from the condition for the adiabatic process, that is,
2.7K
01:21Joule-Thomson Effect
3.5K
The Joule-Thomson effect, also known as the Joule-Kelvin effect, describes the temperature change of a fluid when it is forced through a valve or porous plug while keeping it in a thermally insulated environment. This experiment is called a throttling process. This is an important effect widely used in refrigeration and the liquefaction of gases.
This experiment forces high-pressure gas through a throttle valve or a porous plug to a lower-pressure region. The gas expands as it passes through to...
This experiment forces high-pressure gas through a throttle valve or a porous plug to a lower-pressure region. The gas expands as it passes through to...
3.5K
01:21Path Between Thermodynamics States
3.1K
Consider the two thermodynamic processes involving an ideal gas that are represented by paths AC and ABC in Figure 1:
3.1K
01:17Bernoulli's Principle: Applications
3.7K
There are many devices and situations in which fluid flows at a constant height and so can be analyzed using Bernoulli's principle. These devices include, but are not limited to, entrainment devices and fluid flow measuring devices.
Entrainment devices use a high fluid speed to create low pressures and, thus, entrain one fluid into another. Some examples of these devices are given below:
Entrainment devices use a high fluid speed to create low pressures and, thus, entrain one fluid into another. Some examples of these devices are given below:
3.7K