scholarly journals Polar and phase domain walls with conducting interfacial states in a Weyl semimetal MoTe2

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Fei-Ting Huang ◽  
Seong Joon Lim ◽  
Sobhit Singh ◽  
Jinwoong Kim ◽  
Lunyong Zhang ◽  
...  
Keyword(s):  
Domain Walls ◽  
Surface States ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Topological Materials ◽  
Phase Domain ◽  
Wall Structures ◽  
Transmission Electron ◽  
Interfacial States ◽  
Protected Surface

Abstract Much of the dramatic growth in research on topological materials has focused on topologically protected surface states. While the domain walls of topological materials such as Weyl semimetals with broken inversion or time-reversal symmetry can provide a hunting ground for exploring topological interfacial states, such investigations have received little attention to date. Here, utilizing in-situ cryogenic transmission electron microscopy combined with first-principles calculations, we discover intriguing domain-wall structures in MoTe2, both between polar variants of the low-temperature(T) Weyl phase, and between this and the high-T higher-order topological phase. We demonstrate how polar domain walls can be manipulated with electron beams and show that phase domain walls tend to form superlattice-like structures along the c axis. Scanning tunneling microscopy indicates a possible signature of a conducting hinge state at phase domain walls. Our results open avenues for investigating topological interfacial states and unveiling multifunctional aspects of domain walls in topological materials.

Scanning tunneling microscopy and atomic force microscopy: New tools for biology

1989 ◽  
Vol 47 ◽  
pp. 778-779
Author(s):  
CE Bracker ◽  
P. K. Hansma
Keyword(s):  
Physical Property ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Small Scale ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
New Family ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron

A new family of scanning probe microscopes has emerged that is opening new horizons for investigating the fine structure of matter. The earliest and best known of these instruments is the scanning tunneling microscope (STM). First published in 1982, the STM earned the 1986 Nobel Prize in Physics for two of its inventors, G. Binnig and H. Rohrer. They shared the prize with E. Ruska for his work that had led to the development of the transmission electron microscope half a century earlier. It seems appropriate that the award embodied this particular blend of the old and the new because it demonstrated to the world a long overdue respect for the enormous contributions electron microscopy has made to the understanding of matter, and at the same time it signalled the dawn of a new age in microscopy. What we are seeing is a revolution in microscopy and a redefinition of the concept of a microscope.Several kinds of scanning probe microscopes now exist, and the number is increasing. What they share in common is a small probe that is scanned over the surface of a specimen and measures a physical property on a very small scale, at or near the surface. Scanning probes can measure temperature, magnetic fields, tunneling currents, voltage, force, and ion currents, among others.

In-Plane Asymmetries on the Ge(111)-c(2×8) Surface Mapped with the Scanning Tunneling Microscope

1992 ◽  
Vol 295 ◽  
Author(s):  
P. Molinàs-Mata ◽  
J. Zegenhagen ◽  
M. Böhringer ◽  
N. Takeuchi ◽  
A. Selloni
Keyword(s):  
Local Density ◽  
Experimental Studies ◽  
Surface States ◽  
Small Sample ◽  
Constant Current ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Energy Electron ◽  
Tunneling Currents ◽  
Insight Into

AbstractWe report on new experimental studies of the Ge(111)-c(2×8) reconstruction performed with low-energy electron diffraction. (LEED) and scanning tunneling microscopy (STM). Weak quarter-order reflections are present in the c(2 × 8) LEED pattern in agreement with previous observations and results of ab initio calculations. In order to gain insight into the predicted splitting of dangling bond states, we compare constant current topographs (CCT's) performed at high-tunneling currents (40.nA) with first-principles calculations of the local density of states (LDOS) 1Å above the surface adatoms and obtain good qualitative agreement. We finally discuss to what extent the STM CCT's at high tunneling currents (small sample-tip distances (STD)) are sensitive to surface states outside the Г point.

scholarly journals Исследование электрофизических свойств квантовых точек антимонида индия: значение формы

2021 ◽  
Vol 55 (3) ◽  
pp. 237
Author(s):  
В.Ф. Кабанов ◽  
А.И. Михайлов ◽  
М.В. Гавриков
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Indium Antimonide ◽  
Spectral Characteristics ◽  
Characteristic Size ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Transmission Electron ◽  
Particle Size Analyzer ◽  
Characteristics Analysis

In this work, we studied the influence of the shape of the indium antimonide quantum dots of on some important electrophysical parameters by spectral characteristics analysis, transmission electron microscopy, scanning tunneling microscopy, a laser particle size analyzer, and scanning electron microscopy. It is shown that the real form of quantum dots (spherical and cubic models) at the same characteristic size will noticeably affect the energy spectrum of the investigated objects and, accordingly, their electrophysical and optical properties.

scholarly journals Nanoscale strain engineering of giant pseudo-magnetic fields, valley polarization, and topological channels in graphene

2020 ◽  
Vol 6 (19) ◽  
pp. eaat9488 ◽  
Author(s):  
C.-C. Hsu ◽  
M. L. Teague ◽  
J.-Q. Wang ◽  
N.-C. Yeh
Keyword(s):  
Magnetic Fields ◽  
Domain Walls ◽  
Quantum Hall ◽  
Strain Engineering ◽  
Scanning Tunneling ◽  
Monolayer Graphene ◽  
Tunneling Microscopy ◽  
One Dimensional ◽  
Valley Polarization ◽  
Topological States

The existence of nontrivial Berry phases associated with two inequivalent valleys in graphene provides interesting opportunities for investigating the valley-projected topological states. Examples of such studies include observation of anomalous quantum Hall effect in monolayer graphene, demonstration of topological zero modes in “molecular graphene” assembled by scanning tunneling microscopy, and detection of topological valley transport either in graphene superlattices or at bilayer graphene domain walls. However, all aforementioned experiments involved nonscalable approaches of either mechanically exfoliated flakes or atom-by-atom constructions. Here, we report an approach to manipulating the topological states in monolayer graphene via nanoscale strain engineering at room temperature. By placing strain-free monolayer graphene on architected nanostructures to induce global inversion symmetry breaking, we demonstrate the development of giant pseudo-magnetic fields (up to ~800 T), valley polarization, and periodic one-dimensional topological channels for protected propagation of chiral modes in strained graphene, thus paving a pathway toward scalable graphene-based valleytronics.

Atomic Structure of the Domain Walls of the Discommensurate Phases in Ge(111)/Ga

1998 ◽  
Vol 05 (01) ◽  
pp. 175-179 ◽  
Author(s):  
Zheng Gai ◽  
Bo Gao ◽  
Hang Ji ◽  
R. G. Zhao ◽  
W. S. Yang
Keyword(s):  
Domain Wall ◽  
Scanning Tunneling Microscopy ◽  
Atomic Structure ◽  
Domain Walls ◽  
Scanning Tunneling ◽  
Wall Structure ◽  
Tunneling Microscopy ◽  
Domain Wall Structure ◽  
Stm Images

We have studied the γ and β discommensurate phases of the Ge(111)/Ga system with scanning tunneling microscopy (STM). On the basis of the features of these phases known from our STM images as well as from previous papers, models of domain-wall structure of both phases have been proposed for further investigations.

Comparative Study of Microstructural Properties for YBa2Cu3O7 Films on Single-crystal and Ni-based Metal Substrates

2005 ◽  
Vol 20 (8) ◽  
pp. 2055-2060 ◽  
Author(s):  
Y. Lin ◽  
H. Wang ◽  
B. Maiorov ◽  
M.E. Hawley ◽  
C.J. Wetteland ◽  
...  
Keyword(s):  
Comparative Study ◽  
Single Crystal ◽  
Ion Beam ◽  
Scanning Tunneling ◽  
Structural Quality ◽  
Microstructural Properties ◽  
Tunneling Microscopy ◽  
Ybco Films ◽  
Metal Substrates ◽  
Transmission Electron

We conducted a comparative study of microstructural properties for YBa2Cu3O7 (YBCO) films on single-crystal MgO and polycrystalline Ni-based metal substrates with ion-beam-assisted deposited (IBAD) MgO as a template. The film grown on the metal substrate shows more crystalline imperfections with density of screw dislocations four times higher than that of the film on single-crystal MgO, as revealed by high-resolution x-ray diffraction (HRXRD). These high-density screw dislocation cores connect well and form bigger clustered grains as detected by scanning tunneling microscopy. Transmission electron microscopy studies confirm that the structural quality of YBCO on the Ni-based alloy is comparable to that on single-crystal MgO. All these factors contribute to our routine fabrication of high-quality YBCO films on metal substrates with critical current densities in self-field as high as those for the films grown on single-crystal MgO substrates. Superconducting properties in fields are also discussed.

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