Correlation-Enhanced Effective Mass of Two-Dimensional Electrons in Mg_xZn_(1−x)O/ZnO Heterostructures
Abstract
We performed combined magnetotransport and cyclotron resonance experiments on two-dimensional electron systems confined in the Mg_xZn_(1−x)O/ZnO heterostructures over a wide range of carrier densities, from 1.9 to 12 × 10¹¹ cm⁻² (3.5 ≲ r_s ≲ 10, where r_s is the Wigner-Seitz radius). As the carrier density was reduced, the transport mass m*∗_(tr) was strongly enhanced. In marked contrast, the effective masses determined from the cyclotron resonance m^∗_(CR) were found to be independent of the carrier density and as large as the bulk effective mass. The large enhancement of m^∗_(tr), which exceeds m^∗_(CR) by ∼60%, at the lowest carrier density with r_s ∼ 10 is purely attributed to the strong electron correlation.
Additional Information
© 2012 American Physical Society. (Received 24 September 2012; published 10 December 2012) We thank R. Kato for his experimental support in the cyclotron resonance measurements. This work was supported in part by a Grant-in-Aid for Scientific Research (S) (Grant No. 21224009) and for Young Scientists (B) (Grant No. 2474022), the "Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program)" from JSPS, and the Strategic International Collaborative Research Program (SICORP) from JST, Japan. The measurements that used an X-band spectrometer were conducted in Research Hub for Advanced Nano Characterization, The University of Tokyo, supported by MEXT, Japan. Y. K. was partly supported by Murata Science Foundation. A. T. was partly supported by a Grant-in-Aid for Young Scientists (A) (Grant No. 23686008) from JSPS, Japan.Attached Files
Published - PhysRevLett.109.246401.pdf
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Additional details
- Eprint ID
- 102301
- Resolver ID
- CaltechAUTHORS:20200402-144734477
- Japan Society for the Promotion of Science (JSPS)
- 21224009
- Japan Society for the Promotion of Science (JSPS)
- 2474022
- Japan Science and Technology Agency
- Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- Murata Science Foundation
- Japan Society for the Promotion of Science (JSPS)
- 23686008
- Created
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2020-04-02Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field