中国物理B ›› 2015, Vol. 24 ›› Issue (6): 67302-067302.doi: 10.1088/1674-1056/24/6/067302

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Disorder-enhanced nuclear spin relaxationat Landau level filling factor one

关童a, Benedikt Friessb, 李永庆a, 颜世申c, Vladimir Umanskyd, Klaus von Klitzingb, Jurgen H. Smetb   

  1. a Beijing National Laboratory for Condensed Matter Physics, Institute of Physics,Chinese Academy of Sciences, Beijing 100190, China;
    b Max Planck Institute for Solid State Research, Heisenbergstraß1, D-70569, Stuttgart, Germany;
    c School of Physics, Shandong University, Jinan 250100, China;
    d Weizmann Institute of Science, Rehovot 76100, Israel
  • 收稿日期:2015-03-17 修回日期:2015-03-25 出版日期:2015-06-05 发布日期:2015-06-05
  • 基金资助:

    Project supported by the National Basic Research Program of China (Grant Nos. 2012CB921703 and 2015CB921102), the National Natural Science Foundation of China (Grant Nos. 91121003, 11374337, and 61425015), the Chinese Academy of Sciences, the BMBF, and the German-Israel Foundation.

Disorder-enhanced nuclear spin relaxation at Landau level filling factor one

Guan Tong (关童)a, Benedikt Friessb, Li Yong-Qing (李永庆)a, Yan Shi-Shen (颜世申)c, Vladimir Umanskyd, Klaus von Klitzingb, Jurgen H. Smetb   

  1. a Beijing National Laboratory for Condensed Matter Physics, Institute of Physics,Chinese Academy of Sciences, Beijing 100190, China;
    b Max Planck Institute for Solid State Research, Heisenbergstraß1, D-70569, Stuttgart, Germany;
    c School of Physics, Shandong University, Jinan 250100, China;
    d Weizmann Institute of Science, Rehovot 76100, Israel
  • Received:2015-03-17 Revised:2015-03-25 Online:2015-06-05 Published:2015-06-05
  • Contact: Li Yong-Qing, Jurgen H. Smet E-mail:yqli@iphy.ac.cn;j.smet@fkf.mpg.de
  • About author:73.40.-c; 73.20.-r; 73.63.Hs
  • Supported by:

    Project supported by the National Basic Research Program of China (Grant Nos. 2012CB921703 and 2015CB921102), the National Natural Science Foundation of China (Grant Nos. 91121003, 11374337, and 61425015), the Chinese Academy of Sciences, the BMBF, and the German-Israel Foundation.

摘要:

The nuclear spin relaxation rate (1/T1) is measured for GaAs two-dimensional (2D) electron systems in the quantum Hall regime with an all-electrical technique for agitating and probing the nuclear spins. A “tilted plateau” feature is observed near the Landau level filling factor ν=1 in 1/T1 versus ν. Both the width and magnitude of the plateau increase with decreasing electron density. At low temperatures, 1/T1 exhibits an Arrhenius temperature dependence within the tilted plateau regime. The extracted energy gaps are up to two orders of magnitude smaller than the corresponding charge transport gaps. These results point to a nontrivial mechanism for the disorder-enhanced nuclear spin relaxation, in which microscopic inhomogeneities play a key role for the low energy spin excitations related to skyrmions.

关键词: nuclear spin relaxation, Landau level filling factor one, skyrmions

Abstract:

The nuclear spin relaxation rate (1/T1) is measured for GaAs two-dimensional (2D) electron systems in the quantum Hall regime with an all-electrical technique for agitating and probing the nuclear spins. A “tilted plateau” feature is observed near the Landau level filling factor ν=1 in 1/T1 versus ν. Both the width and magnitude of the plateau increase with decreasing electron density. At low temperatures, 1/T1 exhibits an Arrhenius temperature dependence within the tilted plateau regime. The extracted energy gaps are up to two orders of magnitude smaller than the corresponding charge transport gaps. These results point to a nontrivial mechanism for the disorder-enhanced nuclear spin relaxation, in which microscopic inhomogeneities play a key role for the low energy spin excitations related to skyrmions.

Key words: nuclear spin relaxation, Landau level filling factor one, skyrmions

中图分类号:  (Electronic transport in interface structures)

  • 73.40.-c
73.20.-r (Electron states at surfaces and interfaces) 73.63.Hs (Quantum wells)