The single-electron transport in a three-ion magnetic molecule modulated by a transverse field
arXiv:1302.4768 · doi:10.1088/0953-8984/26/19/195301
Abstract
We study single-electron transport in a three-ion molecule with strong uniaxial anisotropy and in the presence of a transverse magnetic field. Two magnetic ions are connected to each other through a third, nonmagnetic ion. The magnetic ions are coupled to ideal metallic leads and a back gate voltage is applied to the molecule, forming a field-effect transistor. The microscopic Hamiltonian describing this system includes inter-ion hopping, on-site repulsions, and magnetic anisotropies. For a range of values of the parameters of the Hamiltonian, we obtain an energy spectrum similar to that of single-molecule magnets in the giant-spin approximation where the two states with maximum spin projection along the uniaxial anisotropy axis are well separated from other states. In addition, upon applying an external in-plane magnetic field, the energy gap between the ground and first excited states of the molecule oscillates, going to zero at certain special values of the field, in analogy to the diabolical points resulting from Berry phase interference in the giant spin model. Thus, our microscopic model provides the same phenomenological behavior expected from the giant spin model of a single-molecule magnet but with direct access to the internal structure of the molecule, thus making it more appropriate for realistic electronic transport studies. To illustrate this point, the nonlinear electronic transport in the sequential tunneling regime is evaluated for values of the field near these degeneracy points. We show that the existence of these points has a clear signature in the I-V characteristics of the molecule, most notably the modulation of excitation lines in the differential conductance.
10 pages, 13 figures
References in corpus (13)
- Will spin-relaxation times in molecular magnets permit quantum information processing?
- Supramolecular Spin Valves
- Electric Field Controlled Magnetic Anisotropy in a Single Molecule
- Magnetic Quantum Tunneling: Insights from Simple Molecule-Based Magnets
- Berry Phase Oscillations of the Kondo Effect in Single-Molecule Magnets
- Theory for transport through a single magnetic molecule: Endohedral N@C60
- Berry-phase blockade in single-molecule magnets
- Kondo effect in single-molecule magnet transistors
- Spin and orbital degrees of freedom in transition metal oxides and oxide thin films studied by soft x-ray absorption spectroscopy
- First-principle studies of the spin-orbit and the Dzyaloshinskii-Moriya interactions in the \{Cu\} single-molecule magnet
- Sequential Tunneling through Molecular Spin Rings
- Asymmetric Berry-Phase Interference Patterns in a Single-Molecule Magnet
- Vibrational detection and control of spin in mixed-valence molecular transistors