scholarly journals Competing magnetic phases and fluctuation-driven scalar spin chirality in the kagome metal YMn6Sn6

2020 ◽  
Vol 6 (51) ◽  
pp. eabe2680
Author(s):  
Nirmal J. Ghimire ◽  
Rebecca L. Dally ◽  
L. Poudel ◽  
D. C. Jones ◽  
D. Michel ◽  
...  
Keyword(s):  
First Principles ◽  
Elevated Temperatures ◽  
Electronic Devices ◽  
Exchange Interactions ◽  
Magnetic Fluctuations ◽  
First Principles Calculations ◽  
Magnetic Phases ◽  
Topological Hall Effect ◽  
External Stimuli ◽  
Large Response

Identification, understanding, and manipulation of novel magnetic textures are essential for the discovery of new quantum materials for future spin-based electronic devices. In particular, materials that manifest a large response to external stimuli such as a magnetic field are subject to intense investigation. Here, we study the kagome-net magnet YMn6Sn6 by magnetometry, transport, and neutron diffraction measurements combined with first-principles calculations. We identify a number of nontrivial magnetic phases, explain their microscopic nature, and demonstrate that one of them hosts a large topological Hall effect (THE). We propose a previously unidentified fluctuation-driven mechanism, which leads to the THE at elevated temperatures. This interesting physics comes from parametrically frustrated interplanar exchange interactions that trigger strong magnetic fluctuations. Our results pave a path to chiral spin textures, promising for novel spintronics.

Comparative Studies on VS2 Bilayer and VS2/Graphene Heterostructure as the Anodes of Li Ion Battery

2021 ◽  
Vol 894 ◽  
pp. 61-66
Author(s):  
Rui Zhi Dong
Keyword(s):  
Binding Energy ◽  
Diffusion Barrier ◽  
First Principles ◽  
Electronic Devices ◽  
Lithium Ion ◽  
First Principles Calculations ◽  
Li Ion Batteries ◽  
Capacity Loss ◽  
Li Ion ◽  
And Diffusion

Due to the development of various mobile electronic devices, such as electric vehicles, rechargeable ion batteries are becoming more and more important. However, the current commercial lithium-ion batteries have obvious defects, including poor safety from Li dendrite and flammable electrolyte, quick capacity loss and low charging and discharging rate. It is very important to find a better two-dimensional material as the anode of the battery to recover the disadvantages. In this paper, first principles calculations are used to explore the performances of VS2 bilayer and VS2 / graphene heterostructure as the anodes of Li ion batteries. Based on the calculation of the valences, binding energy, intercalation voltage, charge transfer and diffusion barrier of Li, it is found that the latter can be used as a better anode material from the perspective of insertion voltage and binding energy. At the same time, the former one is better in terms of diffusion barrier. Our study provides a comprehensive understanding on VS2 based 2D anodes.

First-Principles Study on Co-Doped ZnO with Oxygen Vacancy

2010 ◽  
Vol 154-155 ◽  
pp. 124-129
Author(s):  
Zhen Zhen Weng ◽  
Zhi Gao Huang ◽  
Wen Xiong Lin
Keyword(s):  
Oxygen Vacancy ◽  
First Principles ◽  
Density Functional ◽  
Exchange Interactions ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Ferromagnetic Exchange ◽  
Ferromagnetic Ground State ◽  
Doped Zno ◽  
Co Doped

The interatomic exchange interactions and the electronic structure of Co-doped ZnO with and without oxygen vacancy have been investigated by the first-principles calculations based on density functional theory. It is found that the oxygen vacancy can strengthen the ferromagnetic exchange interaction between Co atoms and might be available for carrier mediation. The oxygen vacancy near to the Co atoms is more favorable for the ferromagnetic ground state.

First-principles Study of the Electronic Structure and Local Moment Interactions in PuAm Alloy

2008 ◽  
Vol 1104 ◽  
Author(s):  
Myung Joon Han ◽  
Xiangang Wan ◽  
Sergej Y Savrasov
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Local Density ◽  
Exchange Interactions ◽  
Kondo Lattice ◽  
First Principles Calculations ◽  
Correlation Effects ◽  
Self Consistent ◽  
5F Electrons ◽  
Zero Moment

AbstractExpected to provide a clue about the origin of zero moment in the bulk phase of Plutonium, Pu1-xAmx alloys have attracted a great attention, in which upon doping the system transforms from the Kondo lattice to the diluted impurity limit. To understand the electronic structure and the magnetic properties of Pu in different crystal environments, we performed fully self-consistent first-principles calculations of the PuAm system based on the local density approximation (LDA) combined with static (LDA+U) and dynamic corrections (LDA+DMFT) for on-site electron correlations. The electronic structure strongly depends on the level of approximation for correlation effects. The exchange interactions between Pu 5f electrons and the Kondo screening strength were estimated and compared, which provide a new insight to Pu magnetism.

Composition-Dependent Basics of Smart Heusler Materials from First- Principles Calculations

2011 ◽  
Vol 684 ◽  
pp. 1-29 ◽  
Author(s):  
Peter Entel ◽  
Antje Dannenberg ◽  
Mario Siewert ◽  
Heike C. Herper ◽  
Markus E. Gruner ◽  
...  
Keyword(s):  
Shape Memory ◽  
First Principles ◽  
Density Functional ◽  
Elevated Temperatures ◽  
Heusler Alloys ◽  
Density Functional Theory Calculations ◽  
First Principles Calculations ◽  
Magnetic Shape Memory ◽  
Functional Theory ◽  
Magnetic Shape Memory Alloy

The structural and magnetic order are the decisive elements which vastly determine the properties of smart ternary intermetallics such as X2YZ Heusler alloys. Here, X and Y are transition metal elements and Z is an element from the III-V group. In order to give a precise prescription of the possibilities to optimize the magnetic shape memory and magnetocaloric effects of these alloys, we use density functional theory calculations. In particular, we outline how one may find new intermetallics which show higher Curie and martensite transformation temperatures when compared with the prototypical magnetic shape-memory alloy Ni2MnGa. Higher operation temperatures are needed for technological applications at elevated temperatures.

Peeling Silicene From Model Silver Substrates in Molecular Dynamics Simulations

2015 ◽  
Vol 82 (10) ◽  
Author(s):  
Zhao Qin ◽  
Zhiping Xu ◽  
Markus J. Buehler
Keyword(s):  
Molecular Dynamics ◽  
First Principles ◽  
Electronic Devices ◽  
Honeycomb Structure ◽  
Atomistic Simulations ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Semiconducting Properties ◽  
Silver Substrate ◽  
Dynamics Simulations

Silicene is a two-dimensional (2D) allotrope of silicon with a rippled or corrugated honeycomb structure in analogy to graphene. Its semiconducting properties make it attractive for developing future nano-electronic devices. However, it has been challenging to obtain its naked form by using a mechanical exfoliation method as what has been applied to graphene. Here, we use fully atomistic simulations with an effective potential for the silver substrate derived from first-principles calculations to investigate possible ways of peeling silicene solely by mechanical force. We find that the peeling direction is critical for exfoliating silicene and the peeling at a 45 deg angle with the substrate is the most efficient one to detach silicene. Our study could help to understand the mechanics of silicene on substrates and guide the technology of isolation of silicene from the substrate on which it is synthesized.

Highly Tunable Electronic Structure and Linear Dichroism in 90° Twisted α-Phosphorus Carbide Bilayer: A First-Principles Calculation

2021 ◽  
Author(s):  
Weiwei Liu ◽  
Hongwei Bao ◽  
Yan Li ◽  
Fei Ma
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Carrier Mobility ◽  
Electronic Devices ◽  
Linear Dichroism ◽  
First Principles Calculation ◽  
First Principles Calculations ◽  
Application Potential ◽  
High Carrier Mobility ◽  
High Carrier

α-phosphorus carbide (α-PC) shares similar puckered structure with black phosphorus and has a high carrier mobility, showing great application potential in the future nano-electronic devices. Based on first-principles calculations, we...

scholarly journals Adsorption of 4,4″-Diamino-p-Terphenyl on Cu(001): A First-Principles Study

Surfaces ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 31-38
Author(s):  
Chang-Tian Wang ◽  
Yan-Fang Zhang ◽  
Shixuan Du
Keyword(s):  
First Principles ◽  
Rotation Angle ◽  
Electronic Devices ◽  
Molecular Devices ◽  
Stable Configuration ◽  
First Principles Calculations ◽  
Adsorption Sites ◽  
Points Of View ◽  
The Stability ◽  
Molecule Surface

Single-molecular devices show remarkable potential for applications in downscale electronic devices. The adsorption behavior of a molecule on a metal surface is of great importance from both fundamental and technological points of view. Herein, based on first-principles calculations, the adsorption of a 4,4″-diamino-p-terphenyl (DAT) molecule on a Cu(001) surface has been systematically explored. The most stable configuration is the DAT molecule lying flat with a rotation angle of 13° relative to the [100] surface direction. It was found that the adsorption sites of benzene rings and nitrogen atoms in the DAT molecule have important influences on the stability of the adsorption configuration. Electron density differences analysis shows that the electrons accumulate at the DAT-Cu(001) interface. The density of states projected on a DAT molecule of DAT/Cu(001) exhibits a metallic character, while the freestanding ones are semiconducting, indicating a strong interaction between the DAT molecule and the Cu(001) surface in the most stable adsorption configuration. These results provide useful information for tuning the properties and functions of DAT molecules, and may offer useful insights for other organic molecule/surface systems.

scholarly journals Chemical stability of hydrogen boride nanosheets in water

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Kurt Irvin M. Rojas ◽  
Nguyen Thanh Cuong ◽  
Hiroaki Nishino ◽  
Ryota Ishibiki ◽  
Shin-ichi Ito ◽  
...  
Keyword(s):  
Chemical Stability ◽  
First Principles ◽  
Electronic Devices ◽  
Proton Exchange ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Boron Hydride ◽  
Two Dimensional Materials ◽  
Bond Network ◽  
Catalytic Applications

AbstractBoron-based two-dimensional materials are of interest for use in electronic devices and catalytic applications, for which it is important that they are chemically stable. Here, we explore the chemical stability of hydrogen boride nanosheets in water. Experiments reveal that mixing hydrogen boride and water produces negligible amounts of hydrogen, suggesting that hydrolysis does not occur and that hydrogen boride is stable in water, which is in contrast to most boron hydride materials. First-principles calculations reveal that the sheets interact weakly with water even in the presence of defects and that negatively charged boron prevents the onset of hydrolysis. We conclude that the charge state of boron and the covalent boron-boron bond network are responsible for the chemical and structural stability. On the other hand, we found that proton exchange with hydrogen boride nanosheets does occur in water, indicating that they become acidic in the presence of water.

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