Kondo Resonance of a Co Atom Exchange Coupled to a Ferromagnetic Tip

Choi, Deung-Jang; Guissart, Sébastien; Ormaza, Maider; Bachellier, Nicolas; Bengone, O.; Simon, Pascal; Limot, L.

doi:10.1021/acs.nanolett.6b02617

Cited by 35 publications

(44 citation statements)

References 59 publications

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“…2a and 2b. It is qualitatively similar to conventional spin-polarized STM [5] and, more generally, to spin valves or to Kondo systems coupled to magnetic electrodes [4,18,38,39]. As illustrated in Fig.…”

supporting

confidence: 71%

Atomic-scale spin sensing with a single molecule at the apex of a scanning tunneling microscope

Verlhac

Bachellier

Garnier

et al. 2019

Science

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Recent advances in scanning probe techniques rely on the chemical functionalization of the probe-tip termination by a single molecule. The success of this approach opens the tantalizing prospect of introducing spin sensitivity through the functionalization by a magnetic molecule. Here, we use a nickelocene-terminated tip (Nc-tip), which offers the possibility of producing spin excitations on the tip apex of a scanning tunneling microscope (STM). We show that when the Nc-tip is a hundred pm away from point contact with a surface-supported object, magnetic effects may be probed through changes in the spin excitation spectrum of nickelocene. We use this detection scheme to simultaneously determine the exchange field and the spin polarization of the sample with atomic-scale resolution. Our findings demonstrate that the Nc-tip is a powerful probe for investigating surface magnetism with STM, from single magnetic atoms to surfaces.

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supporting

confidence: 71%

Atomic-scale spin sensing with a single molecule at the apex of a scanning tunneling microscope

Verlhac

Bachellier

Garnier

et al. 2019

Science

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“…10,11,[47][48][49] The coupling is |J| ≈ 1.3 meV at the shortest probed Fe-Cc distance, similar to other exchange coupled systems. 45,50 Our simulations also capture the line shape asymmetry observed experimentally.…”

Section: Cc-tip: Kondo Effectsupporting

confidence: 64%

The Kondo Effect of a Molecular Tip As a Magnetic Sensor

et al. 2020

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A single molecule offers to tailor and control the probing capability of a scanning tunneling microscope when placed on the tip. With the help of first-principles calculations, we show that on-tip spin sensitivity is possible through the Kondo ground state of a spin S = 1/2 cobaltocene molecule. When attached to the tip apex, we observe a reproducible Kondo resonance, which splits apart upon tuning the exchange coupling of cobaltocene to an iron atom on the surface. The spin-split Kondo resonance provides quantitative information on the exchange field and on the spin polarization of the iron atom. We also demonstrate that molecular vibrations cause the emergence of Kondo side peaks, which, unlike the Kondo resonance, are sensitive to cobaltocene adsorption. 1Introduction. The decoration of metal probe-tips by a molecule intentionally picked up from a surface has proven to be a powerful method to improve the measurement capabilities of a scanning tunneling microscope (STM). The degrees of freedom of the molecule introduce tip-surface interactions across the vacuum gap that are usually absent when using a metallic apex. These interactions can endow STM with an enhanced sub-molecular resolution, 1-3 and provide new chemical insight. [4][5][6][7] Detailed information can be gathered about single molecules on a surface and the way they interact among each other, which is of interest to chemistry and biology. 8To probe magnetic effects with a molecular tip it is necessary to have a magnetic molecule at the tip apex. Recently, a tip decorated with a nickelocene molecule 9 [Ni(C 5 H 5 ) 2 ] was used to monitor surface magnetism through the inelastic component of the tunneling current, 10,11 which provides an electrical access to the nickelocene spin states. 12 An exciting alternative could consist in using a magnetic molecule undergoing a Kondo effect, which is quite common for magnetic molecules adsorbed on metal surfaces. 13 This ubiquitous quantum phenomenon occurs when a magnetic impurity -molecule or atom-couples to a non-magnetic host metal. 14 The conduction electrons of the metal spin-screen the impurity to form a singlet below a temperature T K . The screening occurs coherently causing the emergence of

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“…We also calculated the impurity spectral function which is found to exhibit characterically different shapes in the three regimes. This not only has implications for the physics of oxides described within the DMFT but could also be directly observed in the tunneling spectra of Hund's impurities adsorbed on metal surfaces [19][20][21] .…”

Section: Introductionmentioning

confidence: 89%

Spin-orbit coupling in three-orbital Kanamori impurity model and its relevance for transition-metal oxides

2017

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We investigate the effects of the spin-orbit coupling (SOC) in a three-orbital impurity model with Kanamori interaction using the numerical renormalization group method. We focus on the impurity occupancy N d = 2 relevant to the dynamical mean-field theory studies of Hund's metals. Depending on the strength of SOC λ we identify three regimes: usual Hund's impurity for |λ| < λc, van-Vleck non-magnetic impurity for λ > λc, and a J = 2 impurity for λ < −λc. They all correspond to a Fermi liquid but with very different quasiparticle phase shifts and different physical properties. The crossover between these regimes is controlled by an emergent scale, the orbital Kondo temperature, λc = T orb K that drops with increasing interaction strength. This implies that oxides with strong electronic correlations are more prone to the effects of the spin-orbit coupling.

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Kondo Resonance of a Co Atom Exchange Coupled to a Ferromagnetic Tip

Cited by 35 publications

References 59 publications

Atomic-scale spin sensing with a single molecule at the apex of a scanning tunneling microscope

Atomic-scale spin sensing with a single molecule at the apex of a scanning tunneling microscope

The Kondo Effect of a Molecular Tip As a Magnetic Sensor

Spin-orbit coupling in three-orbital Kanamori impurity model and its relevance for transition-metal oxides

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