Room temperature spin relaxation in quantum dot based spin-optoelectronic devices

Henning Höpfner; Mingyuan Li; Arne Ludwig; Astrid Ludwig; Frank Stromberg; Heiko Wende; Werner Keune; Dirk Reuter; Andreas D. Wieck; Nils C. Gerhardt; Martin R. Hofmann

doi:10.1117/12.907821

20 February 2012 Room temperature spin relaxation in quantum dot based spin-optoelectronic devices

Henning Höpfner, Mingyuan Li, Arne Ludwig, Astrid Ludwig, Frank Stromberg, Heiko Wende, Werner Keune, Dirk Reuter, Andreas D. Wieck, Nils C. Gerhardt, Martin R. Hofmann

Author Affiliations +

Proceedings Volume 8260, Ultrafast Phenomena and Nanophotonics XVI; 82600A (2012) https://doi.org/10.1117/12.907821
Event: SPIE OPTO, 2012, San Francisco, California, United States

Abstract

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.

Citation Download Citation

Henning Höpfner, Mingyuan Li, Arne Ludwig, Astrid Ludwig, Frank Stromberg, Heiko Wende, Werner Keune, Dirk Reuter, Andreas D. Wieck, Nils C. Gerhardt, and Martin R. Hofmann "Room temperature spin relaxation in quantum dot based spin-optoelectronic devices", Proc. SPIE 8260, Ultrafast Phenomena and Nanophotonics XVI, 82600A (20 February 2012); https://doi.org/10.1117/12.907821

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available