Related Experiment Video
Updated: Jul 24, 2025
06:53
Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
2.0K
Anomalous electronic transport in high-mobility Corbino rings
Sujatha Vijayakrishnan1, F Poitevin1, Oulin Yu1
1Department of Physics, McGill University, Montréal, Québec, Canada.
Nature Communications
|July 3, 2023
Summary
We observed unusual temperature-dependent resistance in GaAs/Al-GaAs Corbino disk samples. Lower density samples showed decreased resistance with warming, unlike higher density samples, suggesting complex electronic transport phenomena.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Semiconductor Physics
Background:
- Two-dimensional electron gases (2DEGs) in GaAs/Al-GaAs heterostructures are crucial for studying fundamental electronic transport.
- Corbino geometry is employed to investigate transport phenomena without edge effects, particularly in high-mobility systems.
- Understanding electron transport at low temperatures is key to exploring quantum effects and novel transport regimes.
Purpose of the Study:
- To investigate low-temperature electronic transport in ultra-high mobility GaAs/Al-GaAs 2DEGs using Corbino geometry.
- To explore the influence of electron density on the temperature dependence of resistance below 1 K.
- To differentiate between bulk transport phenomena and potential edge effects in 2DEG systems.
Main Methods:
- Low-temperature electronic transport measurements were conducted on two multi-terminal Corbino disk samples.
- Samples featured ultra-high electron mobility (≳20 × 10⁶ cm²/Vs) and distinct electron densities (1.7 and 3.6 × 10¹¹ cm⁻²).
- Transport measurements were also performed on large van der Pauw samples with identical heterostructures for comparison.
Main Results:
- A non-monotonic temperature dependence of resistance was observed in both Corbino samples below 1 K.
- The sample with lower electron density exhibited a sharp decrease in resistance with increasing temperature.
- Conversely, the higher density sample showed an opposite behavior, with resistance increasing with temperature.
- Van der Pauw measurements confirmed monotonic resistivity behavior, highlighting the significance of the Corbino geometry.
Conclusions:
- The observed non-monotonic behavior in Corbino samples suggests deviations from simple metallic or diffusive transport.
- Results point towards the influence of electron-electron interactions and varying length scales governing ballistic and hydrodynamic transport.
- The findings may be explained by phenomena such as the Gurzhi effect, particularly in the context of electron-electron scattering in high-mobility 2DEGs.
Related Concept Videos
01:23Magnetic Field due to Moving Charges
8.9K
A stationary charge creates and interacts with the electric field, while a moving charge creates a magnetic field.
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
8.9K
01:14π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
1.2K
In aromatic compounds, such as benzene, the circulation of (4n + 2) π-electrons sets up a diamagnetic or diatropic ring current around the perimeter of the molecule. This current induces a magnetic field that opposes the external field inside the ring and reinforces it on the outside. The protons in benzene are deshielded and exhibit high chemical shifts in the range 6.5–8.5 ppm. The shielding effect at the center of the ring is evident in complex aromatic molecules, such as...
1.2K
01:31Ferromagnetism
2.4K
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
2.4K
01:24Electron Carriers
85.3K
Electron carriers can be thought of as electron shuttles. These compounds can easily accept electrons (i.e., be reduced) or lose them (i.e., be oxidized). They play an essential role in energy production because cellular respiration is contingent on the flow of electrons.
Over the many stages of cellular respiration, glucose breaks down into carbon dioxide and water. Electron carriers pick up electrons lost by glucose in these reactions, temporarily storing and releasing them into the electron...
Over the many stages of cellular respiration, glucose breaks down into carbon dioxide and water. Electron carriers pick up electrons lost by glucose in these reactions, temporarily storing and releasing them into the electron...
85.3K
03:02Colors and Magnetism
12.0K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
12.0K
01:12Fermi Level Dynamics
286
The vacuum level denotes the energy threshold required for an electron to escape from a material surface. It is usually positioned above the conduction band of a semiconductor and acts as a benchmark for comparing electron energies within various materials.
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
286