Pushing Bits Through a Spin Wire

Abstract

Viewpoint: Pushing Bits Through a Spin Wire Shigeki Onoda, Condensed Matter Theory Laboratory, RIKEN, Wako 351-0198, Japan Published May 7, 2012 | Physics 5, 53 (2012) | DOI: 10.1103/Physics.5.53 Short chains of iron atoms deposited on a metal surface could be used to transmit bits of magnetic information. Information Transfer by Vector Spin Chirality in Finite Magnetic Chains Matthias Menzel, Yuriy Mokrousov, Robert Wieser, Jessica E. Bickel, Elena Vedmedenko, Stefan Blügel, Stefan Heinze, Kirsten von Bergmann, André Kubetzka, and Roland Wiesendanger Phys. Rev. Lett. 108, 197204 (2012) Published May 7, 2012 | PDF (free) +Enlarge image Figure 1 APS/Alan Stonebraker Figure 1 An open spin chain engineered on the surface. Spins (arrows) are accommodated at iron sites (spheres). A thermal average of the vector spin chirality κi,i+1 formed by two neighboring spins Si and Si+1 at site i and i+1 always points to the y direction because of the antisymmetric Dzyaloshinskii-Moriya interaction implemented by the artificial structure. The magnetic field hz acting on an edge pins the otherwise fluctuating spin spiral over a whole finite-size spin chain. In the quest to use spin for quantum communication, researchers are constantly looking for new types of magnetic phases. A promising route for this control in solids is to exploit vector spin chirality. This is a pseudovector quantity formed by two neighboring atoms’ electronic spins that breaks parity and mirror symmetries. It is usually present together with cycloidal magnetism, but can be exploited as a sort of independent, hidden order parameter in the context of magnetism [1, 2]. Recent searches for magnetically induced ferroelectricity, or multiferroics, have proven that this quantity is linearly coupled to, and probed by, the electric polarization because of the relativistic spin-orbit coupling [3]. Thus the coupling between vector spin chirality and the electric polarization might provide a route to an efficient electric control of magnetism for applications. Furthermore, this coupling also has potential application for spintronics devices, in the form of finite spin systems hosted by artificial atomic structures deposited on a surface [4, 5]. Now, writing in Physical Review Letters, Matthias Menzel at the University of Hamburg, Germany, and colleagues show that iron biatomic chains, which should have the requisite spin spiral as its ground state, could be an excellent platform for such devices [6]. Combining calculations with scanning tunneling microscopy (STM) images of these iron chains, which behave as “spin wires,” the authors suggest such systems could be useful for transmitting bits of magnetic information.