Berlin 2018 – wissenschaftliches Programm
O 5.3: Vortrag
Montag, 12. März 2018, 11:15–11:30, MA 042
Photoemission study of the spin transition of Fe(phen)2(SCN)2 films on Au(111) — •Johannes Stöckl1,2, Benito Arnoldi1,2, Juliusz A. Wolny1, Volker Schünemann1, Benjamin Stadtmüller1,2,3, and Martin Aeschlimann1,2 — 1Dept. of Physics, University of Kaiserslautern, Erwin-Schrödinger-Str. 46, 67663 Kl, Ger — 2Research Center OPTIMAS, Erwin-Schrödinger-Str. 46, 67663 Kl, Ger — 3Graduate School Materials Science in Mainz, Erwin-Schrödinger-Str. 46, 67663 Kl, Ger
Spin-crossover (SCO) complexes are highly desirable materials for next generation molecular spintronic applications since their electrical, magnetic and optical properties can be controlled by an external stimuli like light or temperature. Here we use angle resolved photoemission electron spectroscopy (ARPES) to investigate the valence band structure of thin films of the prototypical SCO complex Fe(phen)2(SCN)2 on Au(111) for the diamagnetic low spin (LS) as well as the paramagnetic high spin (HS) state. We identify the spectroscopic fingerprints of the HS and LS state by direct comparison of the PES data recorded at room temperature as well as at 40K. In the LS state at LT, the intensity and energetic position of the HOMO-peak of the SCO materials is clearly different compared to the HS state at RT. The magnitude of the observed changes, i.e., the size of the energy shift, strongly dependents on the thickness of the film. Crucially, we show that optical excitation with CW as well as fs light sources can be used to restore the spectroscopic signature of the HS state after the temperature induced transition, i.e., to induce the LS-HS transion.