Anomalous High-Temperature Magnetoresistance in a Dilute 2D Hole System

We report an unusual magnetoresistance that strengthens with the temperature in a dilute two-dimensional (2D) hole system in GaAs/AlGaAs quantum wells with densities p=1.98-0.99×10^{10}/cm^{2} where r_{s}, the ratio between Coulomb energy and Fermi energy, is as large as 20-30. We show that, while t...

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Bibliographic Details
Published in:Physical review letters 2023-06, Vol.130 (26), p.266302-266302, Article 266302
Main Authors: Kumar, Arvind Shankar, Liu, Chieh-Wen, Liu, Shuhao, Gao, Xuan P A, Levchenko, Alex, Pfeiffer, Loren N, West, Kenneth W
Format: Article
Language:English
Subjects:
Cold Temperature
Hydrodynamics
Temperature
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Summary:We report an unusual magnetoresistance that strengthens with the temperature in a dilute two-dimensional (2D) hole system in GaAs/AlGaAs quantum wells with densities p=1.98-0.99×10^{10}/cm^{2} where r_{s}, the ratio between Coulomb energy and Fermi energy, is as large as 20-30. We show that, while the system exhibits a negative parabolic magnetoresistance at low temperatures (≲0.4  K) characteristic of an interacting Fermi liquid, a positive magnetoresistance emerges unexpectedly at higher temperatures, and grows with increasing temperature even in the regime T∼E_{F}, close to the Fermi energy. This unusual positive magnetoresistance at high temperatures can be attributed to the viscous transport of 2D hole fluid in the hydrodynamic regime where holes scatter frequently with each other. These findings give insight into the collective transport of strongly interacting carriers in the r_{s}≫1 regime and new routes toward magnetoresistance at high temperatures.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.130.266302