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In recent years, neural networks have achieved phenomenal success across a wide range of applications. They have also proven useful for solving differential equations. The focus of this work is on the Poisson–Boltzmann equation (PBE) that governs the electrostatics of a metal–oxide–semiconductor capacitor. We were motivated by the question of whether a neural network can effectively learn the solution of PBE using the methodology pioneered by Lagaris et al. [IEEE Trans. Neural Netw. 9 (1998)]. In this method, a neural network is used to generate a set of trial solutions that adhere to the boundary conditions, which are then optimized using the governing equation. However, the challenge with this method is the lack of a generic procedure for creating trial solutions for intricate boundary conditions. We introduce a novel method for generating trial solutions that adhere to the Robin and Dirichlet boundary conditions associated with the PBE. Remarkably, by optimizing the network parameters, we can learn an optimal trial solution that accurately captures essential physical insights, such as the depletion width, the threshold voltage, and the inversion charge. Furthermore, we show that our functional solution can extend beyond the sampling domain. [ABSTRACT FROM AUTHOR]

Borophene, the lightest member of mono-elemental 2D materials family, has attracted much attention due to its intriguing polymorphism. Among many polymorphs, digitally discovered 8-Pmmn stands out owing to its unique tilted-Dirac fermions. However, the property of interfaces between 8-Pmmn and metal substrates has so far remained unexplored, which has critical importance of its application in any electronic devices. Here, with the help of density functional theory, we show that the unique tilted-Dirac property is completely lost when 8-Pmmn borophene is interfaced with common electrode materials such as Au, Ag, and Ti. This is attributed to the high chemical reactivity of borophene as observed from crystal orbital Hamilton population and electron localization function analysis. In an effort to restore the Dirac property, we insert a graphene/hexagonal-boron-nitride (hBN) layer between 8-Pmmn and metal, a technique used in recent experiments for other 2D materials. We show that while the insertion of graphene successfully restores the Dirac nature for all three metals, hBN fails to do so while interfacing with Ti. The quantum chemical insights presented in this work may aid in to access the Dirac properties of 8-Pmmn in experiments. [ABSTRACT FROM AUTHOR]

A recent demonstration of nonvolatile resistive switching in monolayer hexagonal boron nitride (h-BN) has paved the way for the development of the thinnest memory devices feasible. Nevertheless, the exact mechanism of such remarkable resistive switching has remained obscure, which may hinder the optimization of such attractive technology. Here, we present the first dynamic description of the resistive switching process in a Ni/monolayer h-BN/Ni device at an atomistic level by employing reactive molecular dynamics simulations. We show that with the application of a suitable bias, the h-BN layer moves vertically and peels off Ni ions from the electrode, which gets adsorbed in the N vacancy center. From density-functional-theory based electron-localization-function calculations, we confirm that N vacancy generates highly delocalized electrons around the vacancy location resulting in the adsorption of Ni ions, though such a phenomenon is not likely in case of B vacancy due to the absence of electronic states around the defect center. We demonstrate the restoration of Ni ions with the application of reverse bias in case of bipolar switching, and by rising temperature in case of unipolar switching, which agrees with the experimental observations. Finally, we conduct ab initio quantum transport calculation to find an increase in zero-bias conductivity of about 7.4 times after the Ni ion adsorption. This atomistic insight enables precise defect-engineering in 2D materials for the realization of h-BN based high-performance memristive crossbar array. [ABSTRACT FROM AUTHOR]

The insertion of a graphene (or h-BN) layer in a two-dimensional (2D) MoS2–metal interface to de-pin the Fermi level has been a common strategy in experiments. Recently, however, the 2D material space has expanded much beyond transition metal dichalcogenides, and it is not clear if the same strategy will work for other materials. Here, we select a family of twelve emerging, commercially available 2D semiconductors with the work function range of 3.8–6.1 eV and study their interfaces with metals in the presence and absence of the graphene buffer layer. Using the density functional theory, we show that the graphene buffer layer preserves the ideal Schottky–Mott rule to a great extent when the interfaces are made with Ag and Ti. However, the h-BN buffer layer does not yield a similar performance since its electrons are not as localized as graphene. It is further observed that even graphene is not very effective in preserving the ideal Schottky–Mott rule while interfacing with high work function metals (Au, Pd, and Pt). The quantum chemical insights presented in this paper could aid in the design of high-performance electronic devices with low contact resistance based on newly developed 2D materials. [ABSTRACT FROM AUTHOR]

Objectives: Leukemia is one of the severe cancer types all around the globe. Even though some chemotherapeutic drugs are available for treating leukemia, they have various side effects. As an alternative approach, herbal drugs are focused on current research to overcome leukemia. The present work was conducted to investigate the antileukemic mechanism of active phytochemical vitexin, which was isolated from ethno-medicine (Prosopis cineraria leaf) used by traditional healers of West Bengal, India. Methods: Antiproliferative mechanisms of selected phyto-compound against K-562 cells were evaluated using cellular uptake, morphological changes, DNA fragmentation, mitochondrial membrane potential and signaling pathways analysis. Key findings: Vitexin exhibited cytotoxicity by reducing mitochondrial membrane potential (32.40%) and causing DNA fragmentation (84.15%). The western blotting study indicated inhibition of cell survival proteins (BCR, ABL, H-RAS, N-RAS, K-RAS and RAF) and expression of apoptotic proteins (p38, BAX and caspase-9) in leukemia cells upon treatment with vitexin. Conclusions: Based on the results, presently investigated phyto-compound vitexin could be considered for developing safe and natural drugs to treat leukemia after conducting suitable preclinical and clinical trials. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) magnetic materials inherit enormous potential to revolutionize next-generation spintronic technology. The majority of prior investigations using 2D ferromagnet-based tunnel junctions have shown encouraging tunnel magnetoresistance (TMR) at low temperatures. Using first-principles-based calculations, here we investigate the magnetic properties of commercially available Cr 2 C crystals at their monolayer limit and reveal their half metallicity properties far beyond room temperature. We then design hetero-multilayer structures combining Cr 2 C with graphene and hexagonal boron nitride (h-BN) and report their magnetoresistance using spin-polarized quantum transport calculations. While graphene based devices, adsorbed on the metal contact, reveal a very high TMR (1200%), it can be further increased to 1500% by changing the barrier layer to h-BN. The dependence of TMR on the number of barrier layers and different metallic electrode materials (Ti, Ag, and Au) are also studied. Our investigation suggests that Cr 2 C based spin valves can serve as the perfect building blocks for room temperature all-2D spintronic devices.