Bio-Inspired Metal-Organic Crystal Interconnect for Spintronic Logic Operations
Ever since its discovery in the 1920’s, the electron spin has become an integral part of quantum mechanics. Electronic spin relates to and explains many properties, such as magnetism, spin-orbit coupling, and more. One important application of spin is in the field of spintronics – the use of spin as a basis for computation. In spintronics, it is not the electron charge but the electron spin that carries information, and this offers opportunities for a new generation of devices combining standard microelectronics with spin-dependent effects that arise from the interaction between spin of the carrier and the magnetic properties of the material. The advantages of these new devices would be nonvolatility, increased data processing speed, and decreased electric power consumption. Spintronics relies on spin-polarization of the electronic current, thus commonly associated with inorganic materials rather than organics due to the high value of spin-orbit coupling required for spin polarization. As organic materials are generally bio-compatible, easier to work with, and cheaper than their inorganic counterparts, they are attractive building blocks for spintronics devices. The recently discovered chiral-induced spin selectivity (CISS) effect – spin-polarization of an electron current in chiral organic systems – paves the way for such utilizations of organic components. This was shown mainly in bio-inspired materials such as peptide monolayers, proteins, and double-stranded DNA. However, the CISS effect, being quantum mechanical in nature, is limited to short conduction distances and durations due to quantum decoherence (~70 nm in dsDNAS).
We present a novel metal-organic system for efficient long-range spin-polarization, as a basis for interconnect between spintronic-based logical devices. Our system is comprised of a chiral phenylalanine-copper crystal, with spin-polarizing properties resulting from a combination of CISS and intrinsic ferromagnetic properties of the crystal. Spin polarized current is carried across the crystals over more than 500 nm, with no decrease in spin polarization, more than 10-fold longer than previous DNA- and peptide-based CISS systems. Moreover, the CISS effect, in combination with internal ferromagnetism of the crystal, enabled the fabrication of a 6-bit memresistor device. This novel metal-organic system thus presents an attractive platform for spin-based logic operations.