scholarly journals Spin mapping of intralayer antiferromagnetism and field-induced spin reorientation in monolayer CrTe2

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Jing-Jing Xian ◽  
Cong Wang ◽  
Jin-Hua Nie ◽  
Rui Li ◽  
Mengjiao Han ◽  
...  
Keyword(s):  
Lattice Structure ◽  
Spin Reorientation ◽  
Atomic Scale ◽  
First Principles Calculations ◽  
Atomic Lattice ◽  
Depth Analysis ◽  
Scanning Tunnelling ◽  
Magnetic Orders ◽  
Tunnelling Microscopy ◽  
Spin Texture

AbstractIntrinsic antiferromagnetism in van der Waals (vdW) monolayer (ML) crystals enriches our understanding of two-dimensional (2D) magnetic orders and presents several advantages over ferromagnetism in spintronic applications. However, studies of 2D intrinsic antiferromagnetism are sparse, owing to the lack of net magnetisation. Here, by combining spin-polarised scanning tunnelling microscopy and first-principles calculations, we investigate the magnetism of vdW ML CrTe2, which has been successfully grown through molecular-beam epitaxy. We observe a stable antiferromagnetic (AFM) order at the atomic scale in the ML crystal, whose bulk is ferromagnetic, and correlate its imaged zigzag spin texture with the atomic lattice structure. The AFM order exhibits an intriguing noncollinear spin reorientation under magnetic fields, consistent with its calculated moderate magnetic anisotropy. The findings of this study demonstrate the intricacy of 2D vdW magnetic materials and pave the way for their in-depth analysis.

Structural and elastic properties of Cu6Sn5 and Cu3Snfrom first-principles calculations

2009 ◽  
Vol 24 (7) ◽  
pp. 2361-2372 ◽  
Author(s):  
Jiunn Chen ◽  
Yi-Shao Lai ◽  
Ping-Feng Yang ◽  
Chung-Yuan Ren ◽  
Di-Jing Huang
Keyword(s):  
Electronic Structure ◽  
Elastic Modulus ◽  
Elastic Properties ◽  
First Principles ◽  
Elastic Anisotropy ◽  
Lattice Structure ◽  
Elastic Stiffness ◽  
First Principles Calculations ◽  
Atomic Lattice ◽  
Microstructure Effect

We investigated the elastic properties of two tin-copper crystalline phases, the η′-Cu6Sn5 and ε-Cu3Sn, which are often encountered in microelectronic packaging applications. The full elastic stiffness of both phases is determined based on strain-energy relations using first-principles calculations. The computed results show the elastic anisotropy of both phases that cannot be resolved from experiments. Our results, suggesting both phases have the greatest stiffness along the c direction, particularly showed the unique in-plane elastic anisotropy associated with the lattice modulation of the Cu3Sn superstructure. The polycrystalline moduli obtained using the Voigt-Reuss scheme are 125.98 GPa for Cu6Sn5 and 134.16 GPa for Cu3Sn. Our data analysis indicates that the smaller elastic moduli of Cu6Sn5 are attributed to the direct Sn–Sn bond in Cu6Sn5. We reassert the elastic modulus and hardness of both phases using the nanoindentation experiment for our calculation benchmark. Interestingly, the computed polycrystalline elastic modulus of Cu6Sn5 seems to be overestimated, whereas that of Cu3Sn falls nicely in the range of reported data. Based on the observations, the elastic modulus of Cu6Sn5 obtained from nanoindentation tests admit the microstructure effect that is absent for Cu3Sn is concluded. Our analysis of electronic structure shows that the intrinsic hardness and elastic modulus of both phases are dominated by electronic structure and atomic lattice structure, respectively.

Atomic-scale imaging of DNA using scanning tunnelling microscopy

Nature ◽  
1990 ◽  
Vol 346 (6281) ◽  
pp. 294-296 ◽  
Author(s):  
Robert J. Driscoll ◽  
Michael G. Youngquist ◽  
John D. Baldeschwieler
Keyword(s):  
Scanning Tunnelling Microscopy ◽  
Atomic Scale ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy

Imaging by Sliding Planes in Scanning Tunnelling Microscopy

1989 ◽  
Vol 159 ◽  
Author(s):  
John D. Todd ◽  
John B. Pethica
Keyword(s):  
Point Defects ◽  
Layered Materials ◽  
Atomic Scale ◽  
Single Atom ◽  
Scanning Tunnelling Microscope ◽  
Mechanical Contact ◽  
Conductance Fluctuations ◽  
Microscope Images ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy

ABSTRACTScanning tunnelling microscope images of layered materials in a non-uhv environment exhibit various anomalous phenomena, including enhanced corrugation heights, periodicity over large areas and a marked absence of point defects. We have modified a precision indentation device to allow STM rastering of a tip across a surface, while simultaneously monitoring mechanical contact. Images we have obtained from this apparatus on an HOPG sample exhibit atomic scale resolution with contact areas much larger than a single atom. Contrast in the image results from periodic conductance fluctuations as the layers of the sample undergo shear in the region of the tip. We provide a model for this process, which explains a variety of curious, and otherwise unrelated phenomena occurring during STM imaging of these materials.

Growth of Graphene Layers on Silicon Carbide

2009 ◽  
Vol 615-617 ◽  
pp. 199-202 ◽  
Author(s):  
Wlodek Strupiński ◽  
Rafał Bożek ◽  
Jolanta Borysiuk ◽  
Kinga Kościewicz ◽  
Andrzej Wysmolek ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Decomposition Temperature ◽  
Atomic Scale ◽  
Graphene Layers ◽  
Transmission Electron ◽  
Scanning Tunnelling ◽  
Tunnelling Microscopy

The so-called “growth” of graphene was performed using a horizontal chemical vapor deposition (CVD) hot-wall reactor. In-situ etching in the mixture (H2-C3H8) was performed prior to growth at 1600oC temperature under 100 mbar. Systematic studies of the influence of the decomposition temperature and time, substrates roughness, etching of the substrates, heating rate, SiC dezorientation and other process parameters on the graphene thickness and quality have been conducted. Morphology and atomic scale structure of graphene was examined by Scanning Tunnelling Microscopy (STM), Transmission Electron Microscopy (TEM) and Raman scattering methods.

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