Chemistry and Nanotechnology
Physics and Electro-Optics

Device for Electric Field Induced Local Magnetization (No. T4-1886)

Lead Researcher: Ron Naaman


A new technology developed by a group of researchers led by Prof. Ron Naaman from the Weizmann Institute, harnesses the advantages of electron spin orientation for memory and information transmission applications. The innovation enables replacement of the traditional current-based semiconductor technologies, yielding faster computing speed, power efficient memory and increased storage capacity. This new spintronic technology is based on organic molecules deposited on a semiconductor surface. It requires less than 1V for operation, with no current induction requirements and, unlike other spintronic technologies, it does not have a magnetic default state, has a simple structure, and most importantly, it enables to produce magnetic domains of 10 nm, overcoming the 50 nm-domain limitation of other spintronic technologies. These attributes are enabled thanks to the chirality of the molecules and absence of ferromagnetic components. This new technology will enable achievement of what is considered the holy grail of designing memory and information transmission, which is the ability to induce and locally manipulate magnetism solely through electric fields, with high switching frequency and magnetic domains of only a few nanometers. 


Low power consuming components in several markets including electric vehicles, storage solutions, medical devices and sensors:

  • Magneto-resistive sensors / components
  • Memory (including MRAM and flash memory devices)
  • Logic components
  • Spin-based transistors
  • Communication components
  • High-power consuming components (e.g. transformers)
  • Spintronic quantum computing.
  • Switching frequency (>1 MHz)
  • Low energy consumption of <1V, (no current required)
  • Operates at room temperature
  • Down to magnetic domains of 10 nm
  • Does not contain any ferromagnetic components.
Technology's Essence

The device is comprised of a GaAs/AlGaAs semiconductor-based heterostructure, which is coated with chiral molecules self-assembled on its surface and below the gate. It hosts a layer of dopants and a two-dimensional electron gas (2DEG) separated by an insulating layer. Crucially, the device does not contain any ferromagnetic material. A robust magnetic moment is switched on or turned off by applying a gate voltage. The spin injection is a manifestation of the recently observed chiral-induced spin-selectivity effect (CISS), which results in coupling between the electron spins and their linear momenta due to the spin-orbit coupling induced by the curvature of the electronic potential in chiral molecules. The device operates on the chemical potential mismatch between the two components, resulting in injection of electrons or holes, which are spin-polarized due to the CISS effect.

Schematic diagram of the GaAs/AlGaAs-chiral molecule hybrid devices. Chiral molecules were adsorbed onto the surface of the 2DEG. In one configuration (A), the structure used 2DEG located 36 nm under the surface. The chiral molecule monolayer is covered with a MgO layer, onto which a gold gate electrode is deposited. In the second configuration (B), the structure used had the 2DEG under the surface; the top gate was absent. Each device is patterned with four contacts, source (S), drain (D) and two transverse electrodes.