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Electron Spin Relaxation in Graphene Nanoribbon Quantum Dots

Speaker: 
Matthias Droth (University of Konstanz, Germany)
Date: 
Wed, 26/02/2014 - 11:00am to 12:00pm
Location: 
Graphene Seminar Room (S16 level 6)
Host: 
Vitor M. Pereira
Event Type: 
Seminars

Abstract

Armchair graphene nanoribbons (aGNR) are promising as a host material for electron spin qubits because of their potential for scalability and long coherence times [1]. The spin lifetime T1 is limited by spin relaxation, where the Zeeman energy is absorbed by lattice vibrations [2], mediated by spin-orbit and electron-phonon coupling. We have calculated T1 by treating all couplings analytically and find that T1 can be in the range of seconds for several reasons: (i) Van Vleck cancellation; (ii) weak spin-orbit coupling; (iii) low phonon density; (iv) vanishing coupling to out-of-plane modes due to the electronic structure of the aGNR. Owing to the vanishing nuclear spin of 12C, T1 is a good measure for overall coherence. These results and recent advances in the controlled production of graphene nanoribbons [3] make this system interesting for classical and quantum spin- tronics applications.

[1] B. Trauzettel, D. V. Bulaev, D. Loss, and G. Burkard, Nature Phys. 3, 192-196 (2007).
[2] M. Droth and G. Burkard, Phys. Rev. B 84, 155404 (2011).
[3] X. Zhang et al., ACS Nano 7,198 (2013).

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