First-principles calculations for charged defects at surfaces, interfaces, and two-dimensional materials in the presence of electric fields

2018 ◽  
Vol 97 (20) ◽  
Author(s):  
Christoph Freysoldt ◽  
Jörg Neugebauer
Keyword(s):  
Electric Fields ◽  
First Principles ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Two Dimensional Materials ◽  
Charged Defects

Two-dimensional ferroelasticity and negative Poisson’s ratios in monolayer YbX (X=S, Se, Te)

2021 ◽  
Author(s):  
Qingwen Lan ◽  
Changpeng Chen
Keyword(s):  
First Principles ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Two Dimensional Materials ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Two-dimensional ferroelastic materials and two-dimensional materials with negative Poisson’s ratios have attracted great interest. Here, using first-principles calculations, we reveal the materials—monolayer YbX (X=S, Se, Te) that harbors both ferroelasticity...

Hydrophobic and antioxidant effects in In, Sn, and Sb based two dimensional materials

2016 ◽  
Vol 45 (8) ◽  
pp. 3244-3246 ◽  
Author(s):  
Keisuke Takahashi ◽  
Lauren Takahashi
Keyword(s):  
First Principles ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Two Dimensional Materials ◽  
Antioxidant Effects

Hydrophobic and antioxidant effects of two dimensional materials Sn, SnSb, InSb, and InSn are investigated with the implementation of first principles calculations.

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.

Ferromagnetism Switched by Hydrogenation in Layered MoS2

2013 ◽  
Vol 744 ◽  
pp. 345-348 ◽  
Author(s):  
Er Jun Kan ◽  
Ming Li
Keyword(s):  
First Principles ◽  
Spin Structure ◽  
Two Dimensional ◽  
Exchange Splitting ◽  
First Principles Calculations ◽  
Two Dimensional Materials ◽  
Ferromagnetic Character ◽  
Strong Exchange ◽  
Magnetic States ◽  
Layered Mos2

Ordered spin structure in two-dimensional materials is critical to the use of such materials in spintronics. Here, based on first-principles calculations, we demonstrated the existence of magnetic homogeneity in integrated two-dimensional structures. Our calculations show that hydrogenated MoS2 can be magnetized with a ferromagnetic character. The doped electrons in 4d orbitals of Mo atoms through hydrogenation lead to strong exchange splitting, which is the mechanism behind the transition of magnetic states. Given the recent progress in chemical control of two-dimensional materials, our results open a new way to produce two-dimensional spintronics.

scholarly journals Interface-induced sign reversal of the anomalous Hall effect in magnetic topological insulator heterostructures

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Fei Wang ◽  
Xuepeng Wang ◽  
Yi-Fan Zhao ◽  
Di Xiao ◽  
Ling-Jie Zhou ◽  
...  
Keyword(s):  
Hall Effect ◽  
Electric Fields ◽  
First Principles ◽  
Berry Phase ◽  
Condensed Matter ◽  
Anomalous Hall Effect ◽  
First Principles Calculations ◽  
Sign Reversal ◽  
Berry Curvature ◽  
Topological Materials

AbstractThe Berry phase picture provides important insights into the electronic properties of condensed matter systems. The intrinsic anomalous Hall (AH) effect can be understood as the consequence of non-zero Berry curvature in momentum space. Here, we fabricate TI/magnetic TI heterostructures and find that the sign of the AH effect in the magnetic TI layer can be changed from being positive to negative with increasing the thickness of the top TI layer. Our first-principles calculations show that the built-in electric fields at the TI/magnetic TI interface influence the band structure of the magnetic TI layer, and thus lead to a reconstruction of the Berry curvature in the heterostructure samples. Based on the interface-induced AH effect with a negative sign in TI/V-doped TI bilayer structures, we create an artificial “topological Hall effect”-like feature in the Hall trace of the V-doped TI/TI/Cr-doped TI sandwich heterostructures. Our study provides a new route to create the Berry curvature change in magnetic topological materials that may lead to potential technological applications.

scholarly journals Dipole-induced Ohmic contacts between monolayer Janus MoSSe and bulk metals

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Ning Zhao ◽  
Udo Schwingenschlögl
Keyword(s):  
First Principles ◽  
Ohmic Contacts ◽  
Electrode Materials ◽  
Electronic Device ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Fermi Level Pinning ◽  
Common Electrode ◽  
Two Sides ◽  
Metallic Electrodes

AbstractUtilizing a two-dimensional material in an electronic device as channel layer inevitably involves the formation of contacts with metallic electrodes. As these contacts can dramatically affect the behavior of the device, we study the electronic properties of monolayer Janus MoSSe in contact with different metallic electrodes by first-principles calculations, focusing on the differences in the characteristics of contacts with the two sides of MoSSe. In particular, we demonstrate that the Fermi level pinning is different for the two sides of MoSSe, with the magnitude resembling that of MoS2 or MoSe2, while both sides can form Ohmic contacts with common electrode materials without any further adaptation, which is an outstanding advantage over MoS2 and MoSe2.

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