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Creators/Authors contains: "Nikonov, Dmitri E."

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  1. Abstract

    A prominent approach to solving combinatorial optimization problems on parallel hardware is Ising machines, i.e., hardware implementations of networks of interacting binary spin variables. Most Ising machines leverage second-order interactions although important classes of optimization problems, such as satisfiability problems, map more seamlessly to Ising networks with higher-order interactions. Here, we demonstrate that higher-order Ising machines can solve satisfiability problems more resource-efficiently in terms of the number of spin variables and their connections when compared to traditional second-order Ising machines. Further, our results show on a benchmark dataset of Booleank-satisfiability problems that higher-order Ising machines implemented with coupled oscillators rapidly find solutions that are better than second-order Ising machines, thus, improving the current state-of-the-art for Ising machines.

     
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    Free, publicly-accessible full text available December 1, 2024
  2. Abstract

    Transition metal trichalcogenides (TMTs) are two-dimensional (2D) systems with quasi-one-dimensional (quasi-1D) chains. These 2D materials are less susceptible to undesirable edge defects, which enhances their promise for low-dimensional optical and electronic device applications. However, so far, the performance of 2D devices based on TMTs has been hampered by contact-related issues. Therefore, in this review, a diligent effort has been made to both elucidate and summarize the interfacial interactions between gold and various TMTs, namely, In4Se3, TiS3, ZrS3, HfS3, and HfSe3. X-ray photoemission spectroscopy data, supported by the results of electrical transport measurements, provide insights into the nature of interactions at the Au/In4Se3, Au/TiS3, Au/ZrS3, Au/HfS3, and Au/HfSe3interfaces. This may help identify and pave a path toward resolving the contemporary contact-related problems that have plagued the performance of TMT-based nanodevices.

    Graphical abstract

    IVcharacteristics of (a) TiS3, (b) ZrS3, and (c) HfS3

     
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  5. Abstract

    The rapid development of computing applications demands novel low‐energy consumption devices for information processing. Among various candidates, magnetoelectric heterostructures hold promise for meeting the required voltage and power goals. Here, a route to low‐voltage control of magnetism in 30 nm Fe0.5Rh0.5/100 nm 0.68PbMg1/3Nb2/3O3‐0.32PbTiO3(PMN‐PT) heterostructures is demonstrated wherein the magnetoelectric coupling is achieved via strain‐induced changes in the Fe0.5Rh0.5mediated by voltages applied to the PMN‐PT. We describe approaches to achieve high‐quality, epitaxial growth of Fe0.5Rh0.5on the PMN‐PT films and, a methodology to probe and quantify magnetoelectric coupling in small thin‐film devices via studies of the anomalous Hall effect. By comparing the spin‐flop field change induced by temperature and external voltage, the magnetoelectric coupling coefficient is estimated to reach ≈7 × 10−8 s m−1at 325 K while applying a −0.75 V bias.

     
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