432 research outputs found
Spin Filtering via Resonant Reflection of Relativistic Surface States
A microscopic approach is developed to scattering of surface states from a
non-magnetic linear defect at a surface with strong spin-orbit interaction.
Spin-selective reflection resonances in scattering of Rashba-split surface
states by an atomic stripe are theoretically discovered in a proof-of-principle
calculation for a model crystal potential. Spin-filtering properties of such
linear defects are analyzed within an envelope-function formalism for a
perturbed surface based on the Rashba Hamiltonian. The continuous Rashba model
is found to be in full accord with the microscopic theory, which reveals the
essential physics behind the scattering resonance. The spin-dependent
reflection suggests a novel mechanism to manipulate spins on the nanoscale.Comment: 6 pages, 4 figures, 1 tabl
Towards a theory of attosecond transient recorder
Laser assisted photoemission by a chirped subfemtosecond extreme ultraviolet
(XUV) pulse is considered within an exactly solvable quantum-mechanical model.
Special emphasis is given to the energy dependence of photoexcitation
cross-section. The streaked spectra are analyzed within the classical picture
of initial time-momentum distribution r_ini(p,t) of photoelectrons mapped to
the final energy scale. The actual time-momentum distribution in the absence of
the probe laser field is shown to be a poor choice for r_ini, and a more
adequate ansatz is suggested. The semiclassical theory offers a simple
practically useful approximation for streaked spectra. Its limitations for
sufficiently long chirped XUV pulses are established.Comment: 9 pages 8 figure
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