Electrically Controlled Bimetallic Junctions for Atomic-Scale Electronics

Abstract

Forming atomic-scale contacts with attractive geometries and material compositions is a long-term goal of nanotechnology. Here, we show that a rich family of bimetallic atomic-contacts can be fabricated in break-junction setups. The structure and material composition of these contacts can be controlled by atomically precise electromigration, where the metal types of the electron-injecting and sink electrodes determine the type of atoms added to, or subtracted from, the contact structure. The formed bimetallic structures include, for example, platinum and aluminum electrodes bridged by an atomic chain composed of platinum and aluminum atoms as well as iron−nickel single-atom contacts that act as a spin-valve break junction without the need for sophisticated spin-valve geometries. The versatile nature of atomic contacts in bimetallic junctions and the ability to control their structure by electromigration can be used to expand the structural variety of atomic and molecular junctions and their span of properties.

Anisotropic Strain-Mediated Growth of Monatomic Co Chains on Unreconstructed Regions of the Au(111) Surface

“…By using low-symmetric substrates, metal atoms can aggregate into quasi-one-dimensionally ordered chains, e.g., Co clusters on a reconstructed carbon-modified tungsten (110) template . For single-metal-atom chains, several synthesizing approaches have been demonstrated, including the mechanically controllable break junction, encapsulation in carbon nanotubes, , and assembly on substrates . Ground-breaking examples are atom-by-atom manipulation assisted by scanning probe microscopy to prepare well-defined gold chains on NiAl(110) , and using vicinal surfaces, e.g., stepped Si(111), Au–Si(553), Cu(775), and Pt(997) as templates to grow 1D chains based on selective step decoration. , By using grain boundaries in two-dimensional (2D) transition-metal dichalcogenides as the template, Pt atoms are incorporated into the lattice to generate uniform single-metal-atom chains along the domain boundary …”

Conductance and assembly of quasi-1D coordination chain molecular junctions with triazole derivatives

“…Incorporating transition metal atoms into molecular junctions has the potential to expand the scope of phenomena in nanoscale devices due to increased spin and orbital degrees of freedom. 1,2 Prior studies suggest that metal atom-containing junctions can serve as qubits, 3–5 switches, 6–9 spin valves, 10–12 and other memory and spintronic devices. 13–15 However, significant challenges to incorporating molecules with metal cores persist.…”