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Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
Published on: June 28, 2018
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Spin effect on the low-temperature resistivity maximum in a strongly interacting 2D electron system.
A A Shashkin1, M Yu Melnikov1, V T Dolgopolov1
1Institute of Solid State Physics, Chernogolovka, Moscow District, 142432, Russia.
Scientific Reports
|March 25, 2022
Summary
In strongly interacting two-dimensional electron systems, resistivity peaks near the metal-insulator transition. This peak temperature, linked to the Fermi temperature, unexpectedly drops in spin-polarizing magnetic fields, suggesting a spin-related origin.
Area of Science:
- Condensed matter physics
- Quantum materials science
- Strongly correlated electron systems
Background:
- Metal-insulator transitions (MIT) in two-dimensional electron systems (2DES) are crucial for understanding electron interactions.
- Strongly interacting 2DES in SiGe/Si/SiGe quantum wells offer a unique platform to study fundamental physics near MIT.
- Previous research has explored MIT but the specific behavior of resistivity peaks in relation to magnetic fields requires further investigation.
Purpose of the Study:
- To investigate the temperature dependence of resistivity near the zero-magnetic-field metal-insulator transition in a strongly interacting 2DES.
- To examine the influence of spin-polarizing magnetic fields on the resistivity peak temperature.
- To compare experimental observations with existing theoretical models and identify discrepancies.
Main Methods:
- Fabrication of ultra-clean SiGe/Si/SiGe quantum wells.
- Electrical transport measurements to determine resistivity.
- Application of varying parallel magnetic fields to probe spin effects.
- Analysis of the temperature at which resistivity exhibits a maximum (T_max).
Main Results:
- Observed an increase in resistivity with decreasing temperature, followed by a drop near the zero-field metal-insulator transition.
- Found that T_max is close to the renormalized Fermi temperature.
- Crucially, T_max decreased with increasing spin-polarizing magnetic field, contrary to expectations based on Fermi temperature scaling.
Conclusions:
- The observed behavior of T_max in spin-polarizing magnetic fields is not explained by current theories.
- The results strongly suggest a spin-related origin for the anomalous temperature dependence of resistivity near the metal-insulator transition.
- This study highlights the importance of electron spin in the physics of strongly interacting 2D systems near criticality.
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