Kondo Effect in a Neutral and Stable All Organic Radical Single Molecule Break Junction

Organic radicals are neutral, purely organic molecules exhibiting an intrinsic magnetic moment due to the presence of an unpaired electron in the molecule in its ground state. This property, added to the low spin–orbit coupling and weak hyperfine interactions, make neutral organic radicals good candidates for molecular spintronics insofar as the radical character is stable in solid state electronic devices. Here we show that the paramagnetism of the polychlorotriphenylmethyl radical molecule in the form of a Kondo anomaly is preserved in two- and three-terminal solid-state devices, regardless of mechanical and electrostatic changes. Indeed, our results demonstrate that the Kondo anomaly is robust under electrodes displacement and changes of the electrostatic environment, pointing to a localized orbital in the radical as the source of magnetism. Strong support to this picture is provided by density functional calculations and measurements of the corresponding nonradical species. These results pave the way toward the use of all-organic neutral radical molecules in spintronics devices and open the door to further investigations into Kondo physics

Konkurrenz und Solidaritaet im laendlichen Raum

Bibliothek Weltwirtschaft Kiel C126,139 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Spin Crossover-Assisted Modulation of Electron Transport in a Single-Crystal 3D Metal–Organic Framework

Molecule-based spin crossover (SCO) materials display likely one of the most spectacular switchable processes. The SCO involves reversible changes in their physicochemical properties (i.e. optical, magnetic, electronic, and elastic) that are coupled with the spin-state change under an external perturbation (i.e. temperature, light, magnetic field, or the inclusion/release of analytes). Although very promising for their future integration into electronic devices, most SCO compounds show two major drawbacks: (i) their intrinsic low conductance and (ii) the unclear mechanism connecting the spin-state change and the electrical conductivity. Herein, we report the controlled single-crystal-to-single-crystal temperature-induced transformation in a robust metal–organic framework, [Fe2(H0.67bdt)3]·9H2O (1), being bdt2– = 1,4-benzeneditetrazolate, exhibiting a dynamic spin-state change concomitant with an increment in the anisotropic electrical conductance. Compound 1 remains intact during the SCO process even after approximately a 15% volume reduction. The experimental findings are rationalized by analyzing the electronic delocalization of the frontier states by means of density-functional theory calculations. The results point to a correlation between the spin-state of the iron and the electronic conductivity of the 3D structure. In addition, the reversibility of the process is proved

Spin Crossover-Assisted Modulation of Electron Transport in a Single-Crystal 3D Metal–Organic Framework

Molecule-based spin crossover (SCO) materials display likely one of the most spectacular switchable processes. The SCO involves reversible changes in their physicochemical properties (i.e. optical, magnetic, electronic, and elastic) that are coupled with the spin-state change under an external perturbation (i.e. temperature, light, magnetic field, or the inclusion/release of analytes). Although very promising for their future integration into electronic devices, most SCO compounds show two major drawbacks: (i) their intrinsic low conductance and (ii) the unclear mechanism connecting the spin-state change and the electrical conductivity. Herein, we report the controlled single-crystal-to-single-crystal temperature-induced transformation in a robust metal–organic framework, [Fe2(H0.67bdt)3]·9H2O (1), being bdt2– = 1,4-benzeneditetrazolate, exhibiting a dynamic spin-state change concomitant with an increment in the anisotropic electrical conductance. Compound 1 remains intact during the SCO process even after approximately a 15% volume reduction. The experimental findings are rationalized by analyzing the electronic delocalization of the frontier states by means of density-functional theory calculations. The results point to a correlation between the spin-state of the iron and the electronic conductivity of the 3D structure. In addition, the reversibility of the process is proved

Spin Crossover-Assisted Modulation of Electron Transport in a Single-Crystal 3D Metal–Organic Framework

Molecule-based spin crossover (SCO) materials display likely one of the most spectacular switchable processes. The SCO involves reversible changes in their physicochemical properties (i.e. optical, magnetic, electronic, and elastic) that are coupled with the spin-state change under an external perturbation (i.e. temperature, light, magnetic field, or the inclusion/release of analytes). Although very promising for their future integration into electronic devices, most SCO compounds show two major drawbacks: (i) their intrinsic low conductance and (ii) the unclear mechanism connecting the spin-state change and the electrical conductivity. Herein, we report the controlled single-crystal-to-single-crystal temperature-induced transformation in a robust metal–organic framework, [Fe2(H0.67bdt)3]·9H2O (1), being bdt2– = 1,4-benzeneditetrazolate, exhibiting a dynamic spin-state change concomitant with an increment in the anisotropic electrical conductance. Compound 1 remains intact during the SCO process even after approximately a 15% volume reduction. The experimental findings are rationalized by analyzing the electronic delocalization of the frontier states by means of density-functional theory calculations. The results point to a correlation between the spin-state of the iron and the electronic conductivity of the 3D structure. In addition, the reversibility of the process is proved

Spin Crossover-Assisted Modulation of Electron Transport in a Single-Crystal 3D Metal–Organic Framework

Molecule-based spin crossover (SCO) materials display likely one of the most spectacular switchable processes. The SCO involves reversible changes in their physicochemical properties (i.e. optical, magnetic, electronic, and elastic) that are coupled with the spin-state change under an external perturbation (i.e. temperature, light, magnetic field, or the inclusion/release of analytes). Although very promising for their future integration into electronic devices, most SCO compounds show two major drawbacks: (i) their intrinsic low conductance and (ii) the unclear mechanism connecting the spin-state change and the electrical conductivity. Herein, we report the controlled single-crystal-to-single-crystal temperature-induced transformation in a robust metal–organic framework, [Fe2(H0.67bdt)3]·9H2O (1), being bdt2– = 1,4-benzeneditetrazolate, exhibiting a dynamic spin-state change concomitant with an increment in the anisotropic electrical conductance. Compound 1 remains intact during the SCO process even after approximately a 15% volume reduction. The experimental findings are rationalized by analyzing the electronic delocalization of the frontier states by means of density-functional theory calculations. The results point to a correlation between the spin-state of the iron and the electronic conductivity of the 3D structure. In addition, the reversibility of the process is proved