2012/05/11 by Yongqing Li, Y. Q. Li, V. Umansky +2 · 13 citations
Physics and Astronomy · #Atomic physics #Condensed matter physics #Electron #Landau quantization #Magnetic properties of thin films #Muon spin spectroscopy #Nuclear physics #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Spin polarization #Superconductivity #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.86.115421
published in Physical Review B 86(11) (American Physical Society) · 13 pages, 11 figures
arxiv created 2012/05/11 · openalex publication_date 2012/09/17 · arxiv updated 2015/06/05 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
In this work, we demonstrate that significant changes in electron temperature and nuclear spin polarization can be created by applying an electric current in a two-dimensional electron system at Landau level filling factor \ensuremathν=1/2. The current induced effects on nuclear spins can be attributed to electron heating and the efficient coupling between the nuclear and electron spin systems at \ensuremathν=1/2. The electron temperature, elevated by the current, can be measured with a thermometer based on the measurement of the nuclear spin relaxation rate. The electron temperature is found to be proportional to the square root of the current density at \ensuremathν=1/2. Electron spin transitions at \ensuremathν=2/3 and 1/2 are utilized for the measurement of the current induced changes in nuclear spin polarization. Consistent results are obtained from these two different methods of nuclear magnetometry. The finite thickness of the electron wave function is found to be important for evaluation of the nuclear spin polarization even in a narrow quantum well. The nuclear spin polarization follows a Curie law dependence on the electron temperature. This work also allows us to evaluate the electron g factor in high magnetic fields as well as the polarization mass of composite fermions.