ABSTRACT
The electrical control and readout of molecular spin states are key for high-density storage. Expectations are that electrically-driven spin and vibrational excitations in a molecule should give rise to new conductance features in the presence of magnetic anisotropy, offering alternative routes to study and, ultimately, manipulate molecular magnetism. Here, we use inelastic electron tunneling spectroscopy to promote and detect the excited spin states of a prototypical molecule with magnetic anisotropy. We demonstrate the existence of a vibron-assisted spin excitation that can exceed in energy and in amplitude a simple excitation among spin states. This excitation, which can be quenched by structural changes in the magnetic molecule, is explained using first-principles calculations that include dynamical electronic correlations.
ABSTRACT
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 prospect of introducing spin sensitivity through functionalization by a magnetic molecule. We used a nickelocene-terminated tip (Nc-tip), which offered the possibility of producing spin excitations on the tip apex of a scanning tunneling microscope (STM). When the Nc-tip was 100 picometers away from point contact with a surface-supported object, magnetic effects could be probed through changes in the spin excitation spectrum of nickelocene. We used this detection scheme to simultaneously determine the exchange field and the spin polarization of iron atoms and cobalt films on a copper surface with atomic-scale resolution.
ABSTRACT
The active control of a molecular spin represents one of the main challenges in molecular spintronics. Up to now spin manipulation has been achieved through the modification of the molecular structure either by chemical doping or by external stimuli. However, the spin of a molecule adsorbed on a surface depends primarily on the interaction between its localized orbitals and the electronic states of the substrate. Here we change the effective spin of a single molecule by modifying the molecule/metal interface in a controlled way using a low-temperature scanning tunneling microscope. A nickelocene molecule reversibly switches from a spin 1 to 1/2 when varying the electrode-electrode distance from tunnel to contact regime. This switching is experimentally evidenced by inelastic and elastic spin-flip mechanisms observed in reproducible conductance measurements and understood using first principle calculations. Our work demonstrates the active control over the spin state of single molecule devices through interface manipulation.
Subject(s)
Antidepressive Agents/adverse effects , Absorptiometry, Photon , Aged , Antidepressive Agents/administration & dosage , Antidepressive Agents, Tricyclic/adverse effects , Bone Density , Confidence Intervals , Depression/complications , Female , Follow-Up Studies , Hip Fractures/etiology , Humans , Odds Ratio , Risk Factors , Selective Serotonin Reuptake Inhibitors/adverse effectsABSTRACT
Among longitudinal stress fractures, tibial fracture was described in 1960 by Devas in the UK, and is still an uncommon occurrence. To our knowledge, longitudinal stress fracture of the fibula has not been described previously, but only the transversal type. Patients complain of pain in the tibial or fibular side of the ankle, whereas the X-rays are normal. However, unusual physical activity is noted in all patients, and the diagnosis is that of a suspected stress fracture. Bone scan shows quite widespread increased radionuclear intake. CT scan shows the stress fracture. Restriction of activity for one month results in complete disappearance of pain in all cases.
