| 1. |
- Sheykhifard, Z., et al.
(author)
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Magnetic graphene/Ni-nano-crystal hybrid for small field magnetoresistive effect synthesized via electrochemical exfoliation/deposition technique
- 2018
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In: Journal of Materials Science-Materials in Electronics. - : Springer Science and Business Media LLC. - 0957-4522 .- 1573-482X. ; 29:5, s. 4171-4178
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Journal article (peer-reviewed)abstract
- Two-dimensional heterostructures of graphene (Gr) and metal/semiconducting elements convey new direction in electronic devices. They can be useful for spintronics because of small spin orbit interaction of Gr as a non-magnetic metal host with promising electrochemical stability. In this paper, we demonstrate one-step fabrication of magnetic Ni-particles entrapped within Gr-flakes based on simultaneous electrochemical exfoliation/deposition procedure by two-electrode system using platinum as the cathode electrode and a graphite foil as the anode electrode. The final product is an air stable hybrid element including Gr flakes hosting magnetic Ni-nano-crystals showing superparamagnetic-like response and room temperature giant magnetoresistance (GMR) effect at small magnetic field range. The GMR effect is originated from spin scattering through ferromagnetic/non-magnetic nature of Ni/Gr heterostructure and interpreted based on a phenomenological spin transport model. Our work benefits from XRD, XPS, Raman, TEM, FTIR and VSM measurements We addressed that how our results can be used for rapid manufacturing of magnetic Gr for low field magneto resistive elements and potential printed spintronic devices.
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| 2. |
- Angizi, S., et al.
(author)
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A comprehensive review on planar boron nitride nanomaterials: From 2D nanosheets towards 0D quantum dots
- 2022
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In: Progress in Materials Science. - : Elsevier BV. - 0079-6425. ; 124
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Journal article (peer-reviewed)abstract
- Moving from two-dimensional hexagonal boron nitride (2D h-BN) flatlands towards their quantum sized zero-dimensional (0D) islands, as the newest member of the h-BN family, has recently opened up novel research areas due to the emergence of unique optical and physicochemical properties, excellent thermal and chemical stability, and desirable biocompatibility. This review elaborates on the fundamental properties of 2D and 0D h-BN nanomaterials and covers the latest progress in the fabrication and applications of BN nanosheets (BNNSs) and quantum dots (BNQDs). Initially, the transformation of properties in h-BN nanomaterials is discussed when moving from the 2D realm towards the 0D quantum zone. Then, top-down and bottom-up synthesis methods of 2D h-BN are reviewed, analyzing each method's advantages and shortcomings. The review will continue explaining the fabrication methods of BNQDs and the impact of synthesis technique on their physiochemical characteristics. Special attention is given to surface chemistry of BNQD nanocrystals that can alter their electronic band structure and optoelectronic properties. Thereafter, detailed discussion on the implementation of BNNSs and BNQDs in various applications, e.g., catalysts, sensors, bioimaging probes, proton exchange membranes, and photocatalytic activators, is provided. At last, an overview of the ongoing challenges and future directions for BNQD research is presented.
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| 3. |
- Angizi, S., et al.
(author)
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Review-Towards the Two-Dimensional Hexagonal Boron Nitride (2D h-BN) Electrochemical Sensing Platforms
- 2020
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In: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 167:12
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Journal article (peer-reviewed)abstract
- Electrochemical sensing performance of two-dimensional hexagonal boron nitride (2D h-BN) has traditionally been suppressed by their intrinsic electrical insulation and deficient electron transportation mechanism. However, the excellent electrocatalytic activity, high specific surface area, N- and B-active edges, structural defects, adjustable band gap through interaction with other nanomaterials, and chemical functionalization, makes 2D h-BN ideal for many sensing applications. Therefore, finding a pathway to modulate the electronic properties of 2D h-BN while the intrinsic characteristics are well preserved, will evolve a new generation of highly sensitive and selective electrochemical (bio)sensors. That is why extensive research has recently focused on the challenge to functionalize 2D h-BN by controlling the surface chemical reactions with external species, particularly metal nanoparticles. This review summarizes the most recent progress in the application of 2D h-BN nanosheets in electrochemical (bio)sensing. We will explore the fabrication techniques of 2D h-BN for electrochemical applications followed by thorough discussion on their advantages, shortcomings, and promising possibilities as (bio)sensing platforms in near future.
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| 4. |
- Majchrzak, P., et al.
(author)
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Switching of the electron-phonon interaction in 1T-VSe2 assisted by hot carriers
- 2021
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In: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 103:24
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Journal article (peer-reviewed)abstract
- We apply an intense infrared laser pulse in order to perturb the electronic and vibrational states in the three-dimensional charge density wave material 1T-VSe2. Ultrafast snapshots of the light-induced hot carrier dynamics and nonequilibrium quasiparticle spectral function are collected using time- and angle-resolved photoemission spectroscopy. The hot carrier temperature and time-dependent electronic self-energy are extracted from the time-dependent spectral function, revealing that incoherent electron-phonon interactions heat the lattice above the charge density wave critical temperature on a timescale of (200±40) fs. Density functional perturbation theory calculations establish that the presence of hot carriers alters the overall phonon dispersion and quenches efficient low-energy acoustic phonon scattering channels, which results in a new quasiequilibrium state that is experimentally observed.
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| 7. |
- Rogers, J., et al.
(author)
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Bypassing the computational bottleneck of quantum-embedding theories for strong electron correlations with machine learning
- 2021
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In: Physical Review Research. - : American Physical Society. - 2643-1564. ; 3:1
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Journal article (peer-reviewed)abstract
- A cardinal obstacle to performing quantum-mechanical simulations of strongly correlated matter is that, with the theoretical tools presently available, sufficiently accurate computations are often too expensive to be ever feasible. Here we design a computational framework combining quantum-embedding (QE) methods with machine learning. This allows us to bypass altogether the most computationally expensive components of QE algorithms, making their overall cost comparable to bare density functional theory. We perform benchmark calculations of a series of actinide systems, where our method accurately describes the correlation effects, reducing by orders of magnitude the computational cost. We argue that, by producing a larger-scale set of training data, it will be possible to apply our method to systems with arbitrary stoichiometries and crystal structures, paving the way to virtually infinite applications in condensed matter physics, chemistry, and materials science.
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