Quantum Chiral Nanocarbons with Intriguing Spin Polarization for Next Generation Chiral Spintronics
Wenhui Niu
1Max Planck Institute of Microstructure Physics, Halle, Germany
Helicene units have recently emerged as transformative building blocks due to the recognized intriguing chiral-induced spin selectivity (CISS) effect. Helical nanographenes (NGs), therefore, have been considered as prospective candidates for generating spin polarization, profiting from their intrinsic embedded helicene units. However, the observation of the CISS effect in helical NGs remains undocumented to date due to the absence of a suitable molecular platform for spin-selective transport. In this work, we report the regioselective synthesis for lateral-extended NGs that incorporate single or double undecabenzo[7]helicene units, respectively. Thanks to the lateral extension, the resultant helical NGs present excellent chiroptical properties including strong circular dichroism intensity and good dissymmetry factors. Magneto-conductive atomic force microscopy (mc-AFM) and magnetoresistance (MR) measurements along with theoretical calculations demonstrate the clear spin polarization behaviors from lateral-extended helical NGs, affording a spin polarization of up to 80% and a robust MR of 1.5% at room temperature. This discovery identifies lateral-extended helical NGs as promising quantum materials for future organic spintronic devices.
Figure 1: Lateral extended helical nanographene with high chiroptical responses and intrinsic spin polarization.