Room Temperature Spin Relaxation in Quantum Dot Based Spin-Optoelectronic Devices

被引:3
作者
Hoepfner, Henning [1 ]
Li, Mingyuan [1 ]
Ludwig, Arne [1 ,2 ]
Ludwig, Astrid [1 ,2 ]
Stromberg, Frank [3 ,4 ]
Wende, Heiko [3 ,4 ]
Keune, Werner [3 ,4 ]
Reuter, Dirk [1 ,2 ]
Wieck, Andreas D. [1 ,2 ]
Gerhardt, Nils C. [1 ]
Hofmann, Martin R. [1 ]
机构
[1] Ruhr Univ Bochum, Photon & Terahertz Technol, D-44801 Bochum, Germany
[2] Ruhr Univ Bochum, Appl Solid State Phys, D-44801 Bochum, Germany
[3] Univ Duisburg Essen, Fac Phys, D-47048 Duisburg, Germany
[4] Univ Duisburg Essen, Ctr Nanointegrat Duisburg Essen CeNIDE, D-47048 Duisburg, Germany
来源
ULTRAFAST PHENOMENA AND NANOPHOTONICS XVI | 2012年 / 8260卷
关键词
spintronics; room temperature; remanence; spin-LED; DYNAMICS; INJECTION; GAAS;
D O I
10.1117/12.907821
中图分类号
TM [电工技术]; TN [电子技术、通信技术];
学科分类号
0808 ; 0809 ;
摘要
Spin-optoelectronic devices have become a field of intensive research in the past few years. Here we present electrical spin injection into spin light-emitting diodes both at room temperature and in magnetic remanence. Our devices consist of a Fe/Tb multilayer spin injection structure with remanent out-of-plane magnetization, a MgO tunnel barrier for efficient spin injection and an InAs quantum dot light-emitting diode. The ground state emission and first excited state emission both show circularly polarized emission in remanence, i.e. without external magnetic fields which is due to spin injection from our ferromagnetic contact. Using a series of samples with varying transport path lengths between the spin injector and the active region, we investigate the spin relaxation length during vertical carrier transport through our devices. Due to our spin injector with remanent out-of-plane magnetization this spin relaxation can be investigated without the need for external magnetic fields which would possibly influence the spin relaxation process. The decrease in circular polarization with increasing injection path length is found to be exponential, indicating drift-based transport which is in accordance with theoretic calculations. From the exponential decay the spin relaxation length of 26 nm as well as a lower bound for the spin injection efficiency of 25% are calculated. Additionally, influences of magnetic field, temperature and current density in the devices on the spin relaxation process are discussed.
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页数:7
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