Independent and coherent transitions between antiferromagnetic states of few-molecule systems
arXiv:2107.07723 · doi:10.1103/PhysRevB.107.245414
Abstract
Spin-electronic devices are poised to become part of mainstream microelectronic technology .Downsizing them, however, faces the intrinsic difficulty that as ferromagnets become smaller, it becomes more difficult to stabilize their magnetic moment. Antiferromagnets are much more stable, and thus research on antiferromagnetic spintronics has developed into a fast-growing field. Here, we provide proof of concept data that allows us to expand the area of antiferromagnetic spintronics to the hitherto elusive level of individual molecules. In contrast to all previous work on molecular spintronics, our detection scheme of the molecule's spin state does not rely on a magnetic moment. Instead, we use field-effect transistor devices constituting of an isolated, contacted single-wall carbon nanotube covalently bound to a limited number of molecular antiferromagnets incorporating four Mn(II) or Co(II) ions. Time-dependent quantum transport measurement along the functionalized nanotube show step-like transitions between several distinct current levels, which we attribute to transitions between different antiferromagnetic states of individual molecular complexes grafted on the nanotube. A statistical analysis of the switching events using factorial cumulants indicates that the cobalt complexes switch independently from each other, while a coherent superposition of the antiferromagnetic spin states of the molecules along the nanotube is observed for the manganese complexes. The long coherence time (several seconds at 100 mK) is made possible by the absence of spin and orbital momentum in the relevant states of the manganese complex, while the cobalt complex includes a significant orbital momentum contribution due to the pseudo-octahedral d metal centers.
arXiv commentincluding supplementary information
References in corpus (26)
- The SIESTA method for ab initio order-N materials simulation
- Efficient index handling of multidimensional periodic boundary conditions
- Density functional method for nonequilibrium electron transport
- Antiferromagnetic spintronics
- Antiferromagnetic spintronics
- Supramolecular Spin Valves
- Spin relaxation in semiconductor quantum dots
- SIESTA: recent developments and applications
- Optical Phonons in Carbon Nanotubes: Kohn Anomalies, Peierls Distortions and Dynamic Effects
- Improvements on non-equilibrium and transport Green function techniques: the next-generation transiesta
- Magnetoresistance through a single molecule
- Tunneling Spectra of Individual Magnetic Endofullerene Molecules
- Factorial cumulants reveal interactions in counting statistics
- Tunable giant magnetoresistance in a single-molecule junction
- Optical detection of single electron transport dynamics
- Spin-State dependent Conductance Switching in Single Molecule-Graphene Junctions
- Electrically addressing the spin of a magnetic porphyrin through covalently connected graphene electrodes
- Indirect exchange coupling between magnetic adatoms in carbon nanotubes
- Detection of interactions via generalized factorial cumulants in systems in and out of equilibrium
- Short-time counting statistics of charge transfer in Coulomb-blockade systems
- Pushing the limits in real-time measurements of quantum dynamics
- Low-frequency Noise in Individual Carbon Nanotube Field-Effect Transistors with Top, Side and Back Gate Configurations: Effect of Gamma Irradiation
- Probing weakly hybridized magnetic molecules by spin-polarized tunneling
- Impact of tunnel barrier strength on magnetoresistance in carbon nanotubes
- Spin-Orbit Coupling Fluctuations as a Mechanism of Spin Decoherence
- Gate-voltage response of a one-dimensional ballistic spin valve without spin-orbit interaction