Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 2: Surface Magnetism and Spin Phenomena

O 2.6: Talk

Monday, March 16, 2015, 12:00–12:15, MA 004

ISTS of Ho atoms and Ho-Fe atom pairs on Pt(111) in the RKKY-coupling regime — •Manuel Steinbrecher¹, Andreas Sonntag¹, Manuel dos Santos Dias², Mohammed Bouhassoune², Samir Lounis², Jens Wiebe¹, Roland Wiesendanger¹, and Alexander Ako Khajetoorians^1,3 — ¹INF, Hamburg University, 20355 Hamburg, Germany — ²PGI-1 and IAS-1, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany — ³IMM, Radboud University, 6525 AJ Nijmegen, The Netherlands

Rare-earth atoms which are adsorbed on surfaces [1] or introduced as metal centers into molecules [2] are regarded as promising quantum-bit candidates due to the strong localization of their 4f-electrons. For the same reason, an electrical read-out of the rare-earth bit’s magnetic state and the coupling of two bits is more challenging than for 3d atoms, where a read-out via inelastic scanning tunneling spectroscopy (ISTS) and coupling via RKKY-interaction has been unambiguously demonstrated [3, 4]. Here, we show magnetic field dependent ISTS at 300 mK on individual Ho adatoms and Ho-Fe pairs on Pt(111) with distances in the RKKY regime. In conflict with [1] there are no signatures of spin-excitations on Ho in the tunneling regime, and the RKKY-coupling strength is below our thermal energy resolution. These results are supported by our ab-initio calculations which show that RKKY interaction of Ho via the Pt(111) conduction electrons is very weak. [1] Miyamachi et al., Nature 503, 242 (2013); [2] Fahrendorf et al., Nat. Comm. 4, 2425 (2014); [3] Khajetoorians et al., PRL 106, 037205 (2012); [4] Khajetoorians et al., Nat. Phys. 8, 497 (2012).