scholarly journals Elastic properties of bulk and low-dimensional materials using van der Waals density functional

2018 ◽  
Vol 98 (1) ◽  
Author(s):  
Kamal Choudhary ◽  
Gowoon Cheon ◽  
Evan Reed ◽  
Francesca Tavazza
Keyword(s):  
Elastic Properties ◽  
Density Functional ◽  
Van Der Waals ◽  
Low Dimensional ◽  
Low Dimensional Materials

scholarly journals Effect of H Adsorption on the Magnetic Properties of an Fe Island on a W(110) Surface

2019 ◽  
Author(s):  
Marko Melander ◽  
Hannes Jonsson
Keyword(s):  
Magnetic Properties ◽  
Data Storage ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Low Dimensional ◽  
Low Dimensional Materials

<p>Low-dimensional materials, such as ultrathin films, nanoislands and wires, are actively being researched due to their interesting magnetic properties and possible technological applications for example in high density data storage. Results of calculations of an Fe nanoisland on a W(110) support are presented here with particular focus on the effect of hydrogen adsorption on its magnetic properties. This is an important consideration since hydrogen is present even under ultra-high vacuum conditions. The calculations are based on density functional theory within the generalized gradient approximation. The adsorption of H atoms is found to strongly decrease the magnetic moment of the Fe atoms they are bound to, down to less than a half in some cases as compared with the clean Fe island. The results show that it may be important to take the presence of hydrogen into account in measurements of magnetic properties of nanoislands.</p>

scholarly journals Image polaritons in van der Waals crystals

Nanophotonics ◽  
2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Sergey G. Menabde ◽  
Jacob T. Heiden ◽  
Joel D. Cox ◽  
N. Asger Mortensen ◽  
Min Seok Jang
Keyword(s):  
Van Der Waals ◽  
Mirror Image ◽  
Propagation Loss ◽  
Strong Light ◽  
New Class ◽  
Close Proximity ◽  
Matter Interaction ◽  
Light Matter Interaction ◽  
Low Dimensional ◽  
Low Dimensional Materials

Abstract Polaritonic modes in low-dimensional materials enable strong light–matter interactions and the manipulation of light on nanometer length scales. Very recently, a new class of polaritons has attracted considerable interest in nanophotonics: image polaritons in van der Waals crystals, manifesting when a polaritonic material is in close proximity to a highly conductive metal, so that the polaritonic mode couples with its mirror image. Image modes constitute an appealing nanophotonic platform, providing an unparalleled degree of optical field compression into nanometric volumes while exhibiting lower normalized propagation loss compared to conventional polariton modes in van der Waals crystals on nonmetallic substrates. Moreover, the ultra-compressed image modes provide access to the nonlocal regime of light–matter interaction. In this review, we systematically overview the young, yet rapidly growing, field of image polaritons. More specifically, we discuss the dispersion properties of image modes, showcase the diversity of the available polaritons in various van der Waals materials, and highlight experimental breakthroughs owing to the unique properties of image polaritons.

scholarly journals Effect of H Adsorption on the Magnetic Properties of an Fe Island on a W(110) Surface

2019 ◽  
Author(s):  
Marko Melander ◽  
Hannes Jonsson
Keyword(s):  
Magnetic Properties ◽  
Data Storage ◽  
Density Functional ◽  
Hydrogen Adsorption ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Low Dimensional ◽  
Low Dimensional Materials

<p>Low-dimensional materials, such as ultrathin films, nanoislands and wires, are actively being researched due to their interesting magnetic properties and possible technological applications for example in high density data storage. Results of calculations of an Fe nanoisland on a W(110) support are presented here with particular focus on the effect of hydrogen adsorption on its magnetic properties. This is an important consideration since hydrogen is present even under ultra-high vacuum conditions. The calculations are based on density functional theory within the generalized gradient approximation. The adsorption of H atoms is found to strongly decrease the magnetic moment of the Fe atoms they are bound to, down to less than a half in some cases as compared with the clean Fe island. The results show that it may be important to take the presence of hydrogen into account in measurements of magnetic properties of nanoislands.</p>

scholarly journals Mott–Hubbard insulating state for the layered van der Waals $$\hbox {FePX}_3$$ (X: S, Se) as revealed by NEXAFS and resonant photoelectron spectroscopy

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Yichen Jin ◽  
Mouhui Yan ◽  
Tomislav Kremer ◽  
Elena Voloshina ◽  
Yuriy Dedkov
Keyword(s):  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
2D Materials ◽  
Van Der Waals ◽  
Deep Understanding ◽  
Density Functional Theory Calculations ◽  
Binding Energies ◽  
Final State ◽  
Spectroscopy Studies ◽  
Low Dimensional

AbstractA broad family of the nowadays studied low-dimensional systems, including 2D materials, demonstrate many fascinating properties, which however depend on the atomic composition as well as on the system dimensionality. Therefore, the studies of the electronic correlation effects in the new 2D materials is of paramount importance for the understanding of their transport, optical and catalytic properties. Here, by means of electron spectroscopy methods in combination with density functional theory calculations we investigate the electronic structure of a new layered van der Waals $$\hbox {FePX}_3$$ FePX 3 (X: S, Se) materials. Using systematic resonant photoelectron spectroscopy studies we observed strong resonant behavior for the peaks associated with the $$3d^{n-1}$$ 3 d n - 1 final state at low binding energies for these materials. Such observations clearly assign $$\hbox {FePX}_3$$ FePX 3 to the class of Mott–Hubbard type insulators for which the top of the valence band is formed by the hybrid Fe-S/Se electronic states. These observations are important for the deep understanding of this new class of materials and draw perspectives for their further applications in different application areas, like (opto)spintronics and catalysis.

scholarly journals Van der Waals interactions in selected allotropes of phosphorus

2015 ◽  
Vol 230 (2) ◽  
Author(s):  
Frederik Bachhuber ◽  
Joerg von Appen ◽  
Richard Dronskowski ◽  
Peer Schmidt ◽  
Tom Nilges ◽  
...  
Keyword(s):  
Density Functional ◽  
Local Density ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Special Focus ◽  
Generalized Gradient ◽  
Long Range Interactions ◽  
Key Factor ◽  
Low Dimensional ◽  
2D And 3D

AbstractSelected allotropes of phosphorus are investigated by different levels of density functional theory (DFT) calculations to evaluate the relative stability orders with a special focus on the role of van der Waals interactions. Phosphorus is an excellent reference system with a large number of allotropes. Starting from low-dimensional molecular (0D, white P) and polymer structures (1D, P nanorods) to layered (2D, black P) and tubular structures (2D and 3D, crystalline forms of red P), covalent structure motifs are interconnected by van der Waals interactions. They are a key factor for the correct energetic description of all P allotropes. A comparative study is carried out within the local density approximation (LDA) and the generalized gradient approximation (GGA), with and without implementation of a dispersion correction by Grimme (GGA-D2). Our intention is to achieve a reasonable agreement of our calculations with experimental data, the plausibility of energy values, and the treatment of long-range interactions. The effect of van der Waals interactions is exemplified for the interlayer distances of black phosphorous and its electronic structure.

Charge transfer at carbon nanotube–graphene van der Waals heterojunctions

Nanoscale ◽  
2016 ◽  
Vol 8 (26) ◽  
pp. 12883-12886 ◽  
Author(s):  
Yuanda Liu ◽  
Fengqiu Wang ◽  
Yujie Liu ◽  
Xizhang Wang ◽  
Yongbing Xu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Carbon Nanotube ◽  
Van Der Waals ◽  
Optoelectronic Devices ◽  
Low Dimensional ◽  
Low Dimensional Materials

Carbon nanotubes and graphene are two most widely investigated low-dimensional materials for photonic and optoelectronic devices.

scholarly journals Advances in Density-Functional Calculations for Materials Modeling

2019 ◽  
Vol 49 (1) ◽  
pp. 1-30 ◽  
Author(s):  
Reinhard J. Maurer ◽  
Christoph Freysoldt ◽  
Anthony M. Reilly ◽  
Jan Gerit Brandenburg ◽  
Oliver T. Hofmann ◽  
...  
Keyword(s):  
Density Functional ◽  
Materials Science ◽  
Inorganic Materials ◽  
The Past ◽  
Biological Matter ◽  
Materials Modeling ◽  
Wide Range ◽  
Low Dimensional ◽  
Low Dimensional Materials

During the past two decades, density-functional (DF) theory has evolved from niche applications for simple solid-state materials to become a workhorse method for studying a wide range of phenomena in a variety of system classes throughout physics, chemistry, biology, and materials science. Here, we review the recent advances in DF calculations for materials modeling, giving a classification of modern DF-based methods when viewed from the materials modeling perspective. While progress has been very substantial, many challenges remain on the way to achieving consensus on a set of universally applicable DF-based methods for materials modeling. Hence, we focus on recent successes and remaining challenges in DF calculations for modeling hard solids, molecular and biological matter, low-dimensional materials, and hybrid organic-inorganic materials.

scholarly journals Current-driven magnetization switching in a van der Waals ferromagnet Fe3GeTe2

2019 ◽  
Vol 5 (8) ◽  
pp. eaaw8904 ◽  
Author(s):  
Xiao Wang ◽  
Jian Tang ◽  
Xiuxin Xia ◽  
Congli He ◽  
Junwei Zhang ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Van Der Waals ◽  
The Other ◽  
Bilayer Structure ◽  
Spin Orbit ◽  
Two Dimensional ◽  
Magnetization Switching ◽  
Spintronic Devices ◽  
Low Dimensional ◽  
Low Dimensional Materials

The recent discovery of ferromagnetism in two-dimensional (2D) van der Waals (vdW) materials holds promises for spintronic devices with exceptional properties. However, to use 2D vdW magnets for building spintronic nanodevices such as magnetic memories, key challenges remain in terms of effectively switching the magnetization from one state to the other electrically. Here, we devise a bilayer structure of Fe3GeTe2/Pt, in which the magnetization of few-layered Fe3GeTe2 can be effectively switched by the spin-orbit torques (SOTs) originated from the current flowing in the Pt layer. The effective magnetic fields corresponding to the SOTs are further quantitatively characterized using harmonic measurements. Our demonstration of the SOT-driven magnetization switching in a 2D vdW magnet could pave the way for implementing low-dimensional materials in the next-generation spintronic applications.

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