| 1. |
- Alekhin, A., et al.
(författare)
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Magneto-optical properties of Au upon the injection of hot spin-polarized electrons across Fe/Au(001) interfaces
- 2019
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Ingår i: Journal of Physics. - : IOP PUBLISHING LTD. - 0953-8984 .- 1361-648X. ; 31:12
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a novel method for the excitation of sizable magneto-optical effects in Au by means of the laser-induced injection of hot spin-polarized electrons in Au/Fe/MgO(001) heterostructures. It is based on the energy- and spin-dependent electron transmittance of Fe/Au interface which acts as a spin filter for non-thermalized electrons optically excited in Fe. We show that after crossing the interface, majority electrons propagate through the Au layer with the velocity on the order of 1 nm fs(-1) (close to the Fermi velocity) and the decay length on the order of 100nm. Featuring ultrafast functionality and requiring no strong external magnetic fields, spin injection results in a distinct magneto-optical response of Au. We develop a formalism based on the phase of the transient complex MOKE response and demonstrate its robustness in a plethora of experimental and theoretical MOKE studies on Au, including our ab initio calculations. Our work introduces a flexible tool to manipulate magneto-optical properties of metals on the femtosecond timescale that holds high potential for active magneto-photonics, plasmonics, and spintronics.
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| 2. |
- Foehlisch, A., et al.
(författare)
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Charge transfer dynamics in molecular solids and adsorbates driven by local and non-local excitations
- 2012
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028. ; 606:11-12, s. 881-885
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Tidskriftsartikel (refereegranskat)abstract
- Charge transfer pathways and charge transfer times in molecular films and in adsorbate layers depend both on the details of the electronic structure as well as on the degree of the initial localization of the propagating excited electronic state. For C6F6 molecular adsorbate films on the Cu(111) surface we determined the interplay between excited state localization and charge transfer pathways. In particular we selectively prepared a free-particle-like LUMO band excitation and compared it to a molecularly localized core-excited C1s -> pi* C6F6 LUMO state using time-resolved two-photon photoemission (tr-2PPE) and core-sole-clock (CHC) spectroscopy, respectively. For the molecularly localized core-excited C1s -> pi* C6F6 LUMO state, we separate the intramolecular dynamics from the charge transfer dynamics to the metal substrate by taking the intramolecular dynamics of the free C6F6 molecule into account Our analysis yields a generally applicable description of charge transfer within molecular adsorbates and to the substrate. (C) 2011 Published by Elsevier B.V.
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| 3. |
- Östrom, Henrik, et al.
(författare)
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Coupling of spin and vibrational degrees of freedom of adsorbates at metal surfaces probed by vibrational sum-frequency generation
- 2013
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 103:13, s. 132403-
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Tidskriftsartikel (refereegranskat)abstract
- Vibrational spectroscopy using sum-frequency generation has been used to investigate the coupling between a ferromagnetic thin film and adsorbed molecules, here CO on Ni/Cu(100). The CO stretching vibration exhibits a strong magnetic contrast with a pronounced temperature dependence, underlining the high sensitivity of this adsorbate-specific spectroscopy method. Our results indicate that the strong temperature dependence is caused by dynamical changes in the surface chemical bond when the CO stretch vibration is coupled to thermally excited external vibrational modes.
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