Many-body effects in magnetic inelastic electron tunneling spectroscopy

Article

关键词: MOLECULE VIBRATIONAL SPECTROSCOPY;    ANDERSON IMPURITY MODEL;    RENORMALIZATION-GROUP;    CARBON NANOTUBES;    KONDO SYSTEM;    QUANTUM-DOT;    TRANSPORT;    TEMPERATURE;    MICROSCOPE;    RESONANCE;   

DOI  :  10.1103/PhysRevB.85.125434

来源: SCIE

【 摘 要 】

Magnetic inelastic electron tunneling spectroscopy (IETS) shows sharp increases in conductance when a new conductance channel associated with a change in magnetic structure is open. Typically, the magnetic moment carried by an adsorbate can be changed by collision with a tunneling electron; in this process the spin of the electron can flip or not. A previous one-electron theory [Phys. Rev. Lett. 103, 176601 (2009)] successfully explained both the conductance thresholds and the magnitude of the conductance variation. The elastic spin flip of conduction electrons by a magnetic impurity leads to the well-known Kondo effect. In the present work, we compare the theoretical predictions for inelastic magnetic tunneling obtained with a one-electron approach and with a many-body theory including Kondo-like phenomena. We apply our theories to a singlet-triplet transition model system that contains most of the characteristics revealed in magnetic IETS. We use two self-consistent treatments (noncrossing approximation and self-consistent ladder approximation). We show that, although the one-electron limit is properly recovered, new intrinsic many-body features appear. In particular, sharp peaks appear close to the inelastic thresholds; these are not localized exactly at thresholds and could influence the determination of magnetic structures from IETS experiments. Analysis of the evolution with temperature reveals that these many-body features involve an energy scale different from that of the usual Kondo peaks. Indeed, the many-body features perdure at temperatures much larger than the one given by the Kondo energy scale of the system.

【 授权许可】

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