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Lecture Bernd Beschoten

Roster

WhenWhere
30 November 2011 FWN-Building 5111.0080, Nijenborgh 4, 9747 AG, Groningen
Speaker: Dr. Bernd Beschoten
Affiliation: II. Physikalisches Institut, RWTH Aachen, Germany
Title: Spin transport in bilayer graphene: Long spin relaxation times at room temperature
Date: Wed Nov 30, 2011
Start: 15.00
Location: FWN-Building 5111.0080
Host: Bart van Wees
Telephone: +31 50 363 4974

Abstract

Graphene is considered as promising candidate for spintronics applications. The reason is the weak spin-orbit coupling, the absent hyperfine interaction and the observation of micrometer long spin relaxation lengths by Tombros et al. [1]. So far most spin transport studies have focused on single layer graphene (SLG). However, bilayer graphene (BLG) has unique electronic properties which differ greatly from those of SLG by its effective mass of carriers, interlayer hopping and electric-field induced band gap.

Our first systematic studies of spin transport in BLG as a function of mobility, minimum conductivity, charge carrier density and temperature reveal the importance of the D'yakonov - Perel' spin scattering mechanism [2]. The spin relaxation time t s scales inversely with the mobility μ of BLG samples both at room temperature and at low temperature. Spin relaxation times of up to 2 ns are observed in samples with the lowest mobility. These times are an order of magnitude longer than any values previously reported for SLG. We discuss the role of intrinsic and extrinsic factors that could lead to the dominance of the DY spin scattering mechanism in BLG.

 

[1] N. Tombros et al., Nature 448, 571 (2007).

[2] T.-Y. Yang et al., Phys. Rev. Lett. 107, 047206 (2011).

 

Last modified:22 October 2012 2.31 p.m.