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O: Fachverband Oberflächenphysik
O 21: Focus Session: Spins on Surfaces studied by Atomic Scale Spectroscopies III
O 21.10: Vortrag
Dienstag, 19. März 2024, 13:00–13:15, MA 004
Atomic scale study on electronic configurations of single titanium atoms on MgO — •Hong T. Bui1,2, We-hyo Seo1,2, Curie Lee1,2, Christoph Wolf1,2, Nicolas Lorente3,4, and Soo-hyon Phark1,2 — 1center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, Korea — 2Ewha Womans University, Seoul, Korea — 3Centro de Física de Materiales, Donostia-San Sebastián, Spain — 4Donostia International Physics Center, Donostia-San Sebastián, Spain
A single Ti adsorbate on two-monolayer (ML) MgO on Ag(100) is a prototypical electron spin two-level system (S = 1/2), which has recently been used to demonstrate quantum gates in on-surface atomic-scale qubit platforms using scanning tunneling microscopy (STM) combined with an electron spin resonance (ESR) [1]. Further advanced multiple-order quantum gates, however, are limited by its short coherence mainly due to the insufficient decoupling from the substrate. In this work, we investigated spin-dependent electronic properties of single Ti adsorbates on a 3-ML MgO using tunneling and ESR spectroscopies. Measurements on Ti on an O-O bridge site show a differential conductance similar to that on the same adsorption site of the 2-ML MgO and reveal S = 1/2, a promising candidate of on-surface spin qubit but with longer coherence. On the other hand, Ti adsorbed on an O-atop, in contrast to that on the 2-ML MgO (S = 1/2), shows inelastic tunneling features and uniaxial out-of-plane magnetic anisotropy, a signature of S > 1/2, which are well supported by DFT and multiplet calculations for the electronic ground state of 3d2 and S = 1.
Keywords: Scanning tunneling microscopy; Electron spin resonance