44 research outputs found
Theoretical Approach to Electroresistance in Ferroelectric Tunnel Junctions
In this paper, a theoretical approach, comprising the non-equilibrium Green's
function method for electronic transport and Landau-Khalatnikov equation for
electric polarization dynamics, is presented to describe polarization-dependent
tunneling electroresistance (TER) in ferroelectric tunnel junctions. Using
appropriate contact, interface, and ferroelectric parameters, measured
current-voltage characteristic curves in both inorganic
(Co/BaTiO/LaSrMnO) and organic (Au/PVDF/W)
ferroelectric tunnel junctions can be well described by the proposed approach.
Furthermore, under this theoretical framework, the controversy of opposite TER
signs observed experimentally by different groups in
Co/BaTiO/LaSrMnO systems is addressed by
considering the interface termination effects using the effective contact
ratio, defined through the effective screening length and dielectric response
at the metal/ferroelectric interfaces. Finally, our approach is extended to
investigate the role of a CoO buffer layer at the Co/BaTiO
interface in a ferroelectric tunnel memristor. It is shown that, to have a
significant memristor behavior, not only the interface oxygen vacancies but
also the CoO layer thickness may vary with the applied bias.Comment: 12 page
Hybrid Piezoelectric-Magnetic Neurons: A Proposal for Energy-Efficient Machine Learning
This paper proposes a spintronic neuron structure composed of a
heterostructure of magnets and a piezoelectric with a magnetic tunnel junction
(MTJ). The operation of the device is simulated using SPICE models. Simulation
results illustrate that the energy dissipation of the proposed neuron compared
to that of other spintronic neurons exhibits 70% improvement. Compared to CMOS
neurons, the proposed neuron occupies a smaller footprint area and operates
using less energy. Owing to its versatility and low-energy operation, the
proposed neuron is a promising candidate to be adopted in artificial neural
network (ANN) systems.Comment: Submitted to: ACM Southeast '1
Non-volatile spin wave majority gate at the nanoscale
A spin wave majority fork-like structure with feature size of 40\,nm, is
presented and investigated, through micromagnetic simulations. The structure
consists of three merging out-of-plane magnetization spin wave buses and four
magneto-electric cells serving as three inputs and an output. The information
of the logic signals is encoded in the phase of the transmitted spin waves and
subsequently stored as direction of magnetization of the magneto-electric cells
upon detection. The minimum dimensions of the structure that produce an
operational majority gate are identified. For all input combinations, the
detection scheme employed manages to capture the majority phase result of the
spin wave interference and ignore all reflection effects induced by the
geometry of the structure