Contributed talk
Embedding a single all-organic di-radical in break junctions
Thomas Y. Baum1, A. Vegliante2, S. Fernández3, M. Vilas Barela3, J. I. Pascual2, D. Peña3 and H. S. J. van der Zant1
1 Kavli Institute of Nanoscience, Delft University of Technology, The Netherlands
2 CIC nanoGUNE-BRTA, Donostia-San Sebastián, Spain
3 CiQUS, Universidade de Santiago de Compostela, Spain
Polycyclic aromatic hydrocarbon radicals are organic molecules with a nonzero total magnetic moment originating from the unpaired electron in the molecules. The magnetic properties of these systems depend on the exact conformation of the molecule and the surrounding electrostatic environment. Embedding this radical in a molecular junction allows for adjustment and control of the spin signature by mechanical manipulation [1] (varying the electrodes distance in a scanning tunneling microscope (STM) or in a mechanically controlled break junction (MCBJ)). Here, we report on the comparison of electronic transport characteristics of a di-radical molecule measured in STM and MCBJ measurement setups. The same fingerprints are found in both systems including similar transitions by mechanical manipulation between spin-flip inelastic electron tunneling spectra (IETS) [2] of a singlet ground state to a zero-bias resonance ascribed to Kondo phenomena. Combining the two measurement platforms offers valuable insights in how the geometrical constraints inherent to the measurement techniques affect the magnetic properties of the molecule.
Figure 1: Representation of a di-radical embedded in a mechanically controlled break junction (MCBJ upper left) and in a scanning tunneling microscope (STM upper-right). Bottom panels: mechanical transitions from spin-flip inelastic spectra to Kondo resonance while increasing the electrodes spacing for (lower-left) MCBJ and (lower-right) STM molecular junction.
[1] T.Y. Baum et al., Nano Letters 2022 22 (20), 8086-8092.
[2] M. Ternes, New J. Phys. 2015 17 063016.
This project received funding from the European Union Horizon 2020 research and innovation program under grant agreement N°863098 – SPRING