Spin-Dependent Scattering From Gated Obstacles in Graphene Systems M.M. Asmar & S.E. UlloaOhio University

OutlineMotivation

The studied system and mathematical approach.

Results and analysis.

Conclusions .

Motivation

N. Tombros, C. Jozsa, M. Popinciuc, H. T. Jonkman,and B. J. van Wees, Nature (London) 448, 571 (2007).

The studied system and the mathematical approach

The Hamiltonian of the system

Rλ0ΔSO

• C. L. Kane and E. J. Mele, PRL 95, 226801 (2005).

The wave functions at the K point : From the analytical form of the wave function we

obtain the following quantities:

Phase shifts.

Differential cross sections.

Total cross sections which are inversely proportional to the elastic scattering time.

Transport cross section which is inversely proportional to the relaxation (transport time) time.

Conductivity, which is proportional to the relaxation time.

A phase shift is acquired The scattering amplitude depends the acquired phase .

D. S. Novikov, PHYSICAL REVIEW B 76, 245435 2007

Results and Analysis for

and

and

and

andResults and Analysis for

when

Conclusions Conserved helicity Destructive interference of back

scattered waves and time reversed back scattered waves The Klein paradox Angular anisotropy in

scattering in agreement with

Intrinsic spin orbit interaction non conserved helicity Angularly isotropic scattering.

Rashba spin orbit interaction long wavelength and small values of the gated obstacle back scattered particle are spin flipped particles.

Broken spin degeneracy doubling in the number of resonances.

Preserved time reversal symmetry No polarization

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