Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 45: Electronic structure I

O 45.5: Vortrag

Mittwoch, 24. März 2010, 11:30–11:45, H33

Temperature dependent quasiparticle renormalization in nickel and iron. — •Ruslan Ovsyannikov, Setti Thirupathaiah, Jaime Sánchez-Barriga, Jörg Fink, and Hermann Dürr — Helmholtz Zentrum Berlin, BESSY II, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany

One of the fundamental consequences of electron correlation effects is that the bare particles in solids become ’dressed’ with an excitation cloud resulting in quasiparticles. Such a quasiparticle will carry the same spin and charge as the original particle, but will have a renormalized mass and a finite lifetime. The properties of many-body interactions are described with a complex function called self energy which is directly accessible to modern high-resolution angle resolved photoemission spectroscopy (ARPES). Ferromagnetic metals like nickel or iron offers the exciting possibility to study the spin dependence of quasiparticle coupling to bosonic modes. Utilizing the exchange split band structure as an intrinsic ’spin detector’ it is possible to distinguish between electron-phonon and electron-magnon coupling phenomena. In this contribution we will report a systematic investigation of the k– and temperature dependence of the electron-boson coupling in nickel and iron metals as well as discuss origin of earlier observed anomalous lifetime broadening of majority spin states of nickel at Fermi level.