Search arXivSearch

arXiv · 1212.3362

Material Targets for Scaling All Spin Logic

Abstract

All-spin logic devices are promising candidates to augment and complement beyond-CMOS integrated circuit computing due to non-volatility, ultra-low operating voltages, higher logical efficiency, and high density integration. However, the path to reach lower energy-delay product performance compared to CMOS transistors currently is not clear. We show that scaling and engineering the nanoscale magnetic materials and interfaces is the key to realizing spin logic devices that can surpass energy-delay performance of CMOS transistors. With validated stochastic nano-magnetic and vector spin transport numerical models, we derive the target material and interface properties for the nanomagnets and channels. We identified promising new directions for material engineering/discovery focusing on systematic scaling of magnetic anisotropy (Hk) with saturation magnetization (Ms), use of perpendicular magnetic anisotropy, and interface spin mixing conductance of ferromagnet/spin channel interface (Gmix). We provide systematic targets for scaling spin logic energy-delay product toward a 2 aJ.ns energy-delay product, comprehending the stochastic noise for nanomagnets.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Sasikanth Manipatruni, Dmitri E. Nikonov, Ian A. Young. 2012-12-13. Material Targets for Scaling All Spin Logic. https://doi.org/10.1103/physrevapplied.5.014002

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Electrical Probing of Dark Excitons through Microwave Permittivity

Excitons in atomically thin semiconductors are almost always probed through their optical signatures, because the short lifetimes of these transient quasiparticles are generally assumed to preclude electrical detection. Here we show that photoexcited excitons in monolayer tungsten disulfide produce a large, optically tunable permittivity at gigahertz frequencies, and that the effect provides a contact-free electrical route to imaging dark excitons at the nanoscale. Using laser-illuminated microwave impedance microscopy, we find that high-purity encapsulated flakes exhibit a purely dielectric response resonant with the exciton spectrum, whereas defect-rich samples are governed by conventional photoconductivity. Spatial mapping of diffusion and sublinear power dependence identify long-lived dark excitons as the dominant contributors, and first-principles modelling of exciton polarizability reproduces the measured susceptibility. Our results establish excitons as optically tunable dielectric elements and introduce microwave microscopy as a direct electrical probe of dark-exciton transport with sub-100 nm resolution.

cond-mat.mes-hall

Relation between the areal rate of Zitterbewegung and Berry curvature in two-band systems

We introduce the Zitterbewegung areal rate operator to study the relation between the orientation of trembling motion and band topology. Constructed from the oscillatory interband displacement and velocity, this operator distinguishes clockwise from anticlockwise motion. For a generic gapped two-band Hamiltonian in two dimensions, we show that the Zitterbewegung areal rate is proportional to the Berry curvature. The derivation uses only spectral projectors and is therefore gauge invariant. We also demonstrate that the Zitterbewegung areal rate operator is time-independent and a constant of motion at each momentum, although the displacement and velocity from which it is constructed oscillate in time. Its sign distinguishes anticlockwise from clockwise Zitterbewegung and coincides with the sign of the Berry curvature. For wave packets narrowly localized around the isolated massive Dirac points, the Zitterbewegung chirality equals the sign of the local Chern contribution. The Chern number can therefore be reconstructed from the orientations of the Zitterbewegung motion around the individual Dirac points.

cond-mat.mes-hall

Substrate-driven topological engineering in plasmonic Su-Schrieffer-Heeger chains

We demonstrate the possibility of engineering the topological band structure of a plasmonic Su-Schrieffer-Heeger (SSH) chain through the interaction with its electromagnetic environment. We find that the long-range interaction of the in-plane modes of the SSH chain with the surface plasmon polaritons of a planar substrate introduces a band hybridization connected to a change of the Zak phase. On the other hand, the short-range interaction with the substrate introduces a band touching, again with a change in the Zak phase. Surprisingly, this second mechanism enables the emergence of topologically protected edge modes for parameters which correspond to the topologically trivial phase for an isolated plasmonic SSH chain. We study these mechanisms by changing the chain-substrate distance and the dimerization parameter. Finally, we discuss the robustness against disorder and, as one example, the impact of the observed effects on the near-field radiative heat transfer and the local density of states along the chain. Our findings pave the way to the engineering of edge modes in plasmonic topological configurations via the coupling to a plasmonic environment.

cond-mat.mes-hall