« décembre 2018 »
L M M J V S D
26 27 28 29 30 1 2
3 4 5 6 7 8 9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31 1 2 3 4 5 6
 
Tous les évènements de Physique à venir

Tous les évènements de Biologie / Chimie à venir

Tous les évènements à venir

Les évènements relevant de la Physique et de la Biologie / Chimie sont représentés en turquoise

Peculiar spin-polarized electronic states on semiconductor surfaces

Mercredi 18 décembre 2013 10:00 - Duree : 1 heure
Lieu : Salle "Remy Lemaire" K 223 (1er étage) bât. K de l’institut Néel/CNRS - 25 rue des martyrs - 38000 Grenoble

Orateur : Kazuyuki SAKAMOTO (Chiba University, Japan)

Generally, the electronic states of opposite spin orientation are considered to be degenerate in nonmagnetic materials due to the presence of bot h time-reversal symmetry and space-inversion symmetry. In a 2D system such as a crystal surface, the latter symmetry is broken and the degeneracy is lifted by spin-orbit coupling. This effect, which is called the Rashba-Bychkov (RB) effect [1], is a novel exotic low-dimensional solid-state property that produces spin-polarized electronic states even for nonmagnetic materials, and is the key factor for operating a spin field-effect transistor [2] that is one of the most prominent semiconductor spintronics devices. In this talk, I first present peculiar RB effects that originate from the symmetry of the surface, such as the abrupt change of the spin polarization vector to a direction that is not possible to point with normal RB effect [3], and the presence of peculiar vortical RB splitting at a point without time-reversal invariance, which was believed to be a critical condition for RB effect [4]. Then, I show results on RB systems with peculiar spin structures, in which the b ackscattering of electron spin with a non-magnetic impurity are considerably suppressed [5], and also discuss the origin of these spin structures based on a combination of the RB effect and the valley degree of freedom [6]. All these novel quantum phenomena are corroborated by the combination of high-resolution photoemission and spin-resolved photoemission measurements, scanning tunneling microscopy, and a state-of-the-art theoretical calculation. [1] Y.A. Bychkov & E.I. Rashba, JETP Lett. 39, 78 (1984). [2] S. Datta & B. Das, APL 56, 665 (1990). [3] K. Sakamoto et al., PRL 102, 096805 (2009). [4] K. Sakamoto et al., PRL 103, 156801 (2009). [5] K. Sakamoto et al., Nature Comm. 4, 2073 (2013). [6] S. Goswami et al., Nature Phys. 3, 41 (2007).

Contact : florence.levy-bertrand@neel.cnrs.fr

Discipline évènement : (Physique)
Entité organisatrice : (Institut Néel / MCBT)
Nature évènement : (Séminaire)
Evènement répétitif : (Séminaire MCBT)
Site de l'évènement : Polygone scientifique

Prévenir un ami par email

Télécharger dans mon agenda

Cafés sciences de Grenoble | UdPPC de Grenoble | Sauvons Le Climat | Cafe des sciences de Vizille
Accueil du site | Secretariat | Espace privé | Suivre la vie du site RSS 2.0 : Tous les evenements Suivre la vie du site RSS 2.0 : Evenements de Physique Suivre la vie du site RSS 2.0 : Evenements de Biologie & Chimie