scholarly journals Evidence for d-Wave Superconductivity in Single Layer FeSe/SrTiO3 Probed by Quasiparticle Scattering Off Step Edges

Nano Letters ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 2497-2502 ◽  
Author(s):  
Zhuozhi Ge ◽  
Chenhui Yan ◽  
Huimin Zhang ◽  
Daniel Agterberg ◽  
Michael Weinert ◽  
...  
Keyword(s):  
Single Layer ◽  
Quasiparticle Scattering ◽  
D Wave ◽  
Step Edges

A New, Nearly Single-Domain Surface Structure of Homoepitaxial Diamondr (001) Films

1996 ◽  
Vol 423 ◽  
Author(s):  
Yalei Kuang ◽  
Naesung Lee ◽  
Andrzej Badzian ◽  
Teresa Badzian ◽  
Tien T. Tsong
Keyword(s):  
Surface Structure ◽  
Natural Diamond ◽  
Single Layer ◽  
Chemical Vapor ◽  
Single Domain ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Plasma Chemical Vapor Deposition ◽  
Boron Doped ◽  
Step Edges

AbstractBoron-doped homoepitaxial diamond films were grown on natural diamond (001) substrates using microwave-assisted plasma chemical vapor deposition techniques. The surface structures were investigated using scanning tunneling microscopy (STM). This showed a dimertype 2×1 reconstruction structure with single-layer steps where dimer rows on the upper terrace are normal to or parallel to the step edges. We found that dimer rows parallel to the step edges are much longer than those normal to the step edges. The nearly single-domain surface structure observed by STM is in agreement with the low-energy electron diffraction (LEED) patterns from these surfaces. The high atomic resolution STM image showed that the local 1×1 configurations exist.

Growth of single-layer boron nitride dome-shaped nanostructures catalysed by iron clusters

Nanoscale ◽  
2016 ◽  
Vol 8 (32) ◽  
pp. 15079-15085 ◽  
Author(s):  
A. La Torre ◽  
E. H. Åhlgren ◽  
M. W. Fay ◽  
F. Ben Romdhane ◽  
S. T. Skowron ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Single Layer ◽  
Iron Clusters ◽  
Step Edges

We report on the growth and formation of single-layer boron nitride dome-shaped nanostructures on the step edges of hexagonal boron nitride flakes mediated by small iron clusters.

scholarly journals COMPETITION BETWEEN SUPERCONDUCTIVITY AND CHARGE STRIPE ORDER IN HIGH-Tc CUPRATES

2000 ◽  
Vol 14 (11) ◽  
pp. 377-384 ◽  
Author(s):  
G. BASKARAN
Keyword(s):  
Hole Concentration ◽  
Single Layer ◽  
High Tc ◽  
Optimal Doping ◽  
Epitaxial Strain ◽  
Stripe Order ◽  
Charge Stripe ◽  
Lattice Coupling ◽  
High Tc Cuprates ◽  
D Wave

Members of the high-T c cuprate family (with defect-free CuO 2 planes) are suggested to have an "Intrinsic single-layer superconductingT c ", larger than the experimentally observed T c , at a given hole concentration. This difference occurs to varying degrees among the different members due to an anomalous response of the d-wave superconducting state to self-generated charge perturbations. In particular, any quasielastic charge stripe order, arising from electron–electron and electron–lattice coupling, can suppress the large intrinsic superconducting T c . Existing experimental results on the wide T c variation in the single-layer cuprate families, such as the low T c (≈ 38 K, 33 K) of LSCO and Bi-2201 compared to the high-T c (≈ 95 K, 98 K) of Tl-2201 and Hg-1201, the strain-induced increase in T c (25 to 50 K) observed in LSCO are qualitatively explained by our mechanism. We predict that under proper epitaxial strain, the T c of LSCO and Bi-2201 should increase from the 30's all the way up to the intrinsic T c ~ 90 K at optimal doping.

Friction at single-layer graphene step edges due to chemical and topographic interactions

Carbon ◽  
2019 ◽  
Vol 154 ◽  
pp. 67-73 ◽  
Author(s):  
Lei Chen ◽  
Zhe Chen ◽  
Xiaoyu Tang ◽  
Wenmeng Yan ◽  
Zhongrong Zhou ◽  
...  
Keyword(s):  
Single Layer ◽  
Single Layer Graphene ◽  
Layer Graphene ◽  
Step Edges

scholarly journals ELECTRONIC STRUCTURE OF KINETIC ENERGY DRIVEN CUPRATE SUPERCONDUCTORS

2008 ◽  
Vol 22 (22) ◽  
pp. 3757-3811 ◽  
Author(s):  
SHIPING FENG ◽  
HUAIMING GUO ◽  
YU LAN ◽  
LI CHENG
Keyword(s):  
Electronic Structure ◽  
Kinetic Energy ◽  
Superconducting State ◽  
Cuprate Superconductors ◽  
Single Layer ◽  
Low Energy ◽  
Spin Representation ◽  
General Description ◽  
Double Peak Structure ◽  
D Wave

In this paper, we review the low energy electronic structure of the kinetic energy driven d-wave cuprate superconductors. We give a general description of the charge-spin separation fermion-spin theory, where the constrained electron is decoupled as the gauge invariant dressed holon and spin. In particular, we show that under the decoupling scheme, the charge-spin separation fermion-spin representation is a natural representation of the constrained electron defined in a restricted Hilbert space without double electron occupancy. Based on the charge-spin separation fermion-spin theory, we have developed the kinetic energy driven superconducting mechanism, where the superconducting state is controlled by both superconducting gap parameter and quasiparticle coherence. Within this kinetic energy driven superconductivity, we have discussed the low energy electronic structure of the single layer and bilayer cuprate superconductors in both superconducting and normal states, and qualitatively reproduced all main features of the angle-resolved photoemission spectroscopy measurements on the single layer and bilayer cuprate superconductors. We show that the superconducting state in cuprate superconductors is the conventional Bardeen-Cooper-Schrieffer like with the d-wave symmetry, so that the basic Bardeen-Cooper-Schrieffer formalism with the d-wave gap function is still valid in discussions of the low energy electronic structure of cuprate superconductors, although the pairing mechanism is driven by the kinetic energy by exchanging spin excitations. We also show that the well-pronounced peak-dip-hump structure of the bilayer cuprate superconductors in the superconducting state and double-peak structure in the normal state are mainly caused by the bilayer splitting.

Crystalline order to a resolution of 4.7 A in the sheath of Methanospirilium hungatii: A cross-beta structure

1984 ◽  
Vol 42 ◽  
pp. 214-215
Author(s):  
Murray Stewart ◽  
T.J. Beveridge ◽  
D. Sprott
Keyword(s):  
Cell Wall ◽  
Single Layer ◽  
Uranyl Acetate ◽  
Optical Diffraction ◽  
Tube Axis ◽  
Basic Subunit ◽  
Beta Structure ◽  
Diffraction Patterns ◽  
Protein Treatment ◽  
General Appearance

The archaebacterium Methanospirillum hungatii has a sheath as part of its cell wall which is composed mainly of protein. Treatment with dithiothreitol or NaOH released the intact sheaths and electron micrographs of this material negatively stained with uranyl acetate showed flattened hollow tubes, about 0.5 μm diameter and several microns long, in which the patterns from the top and bottom were superimposed. Single layers, derived from broken tubes, were also seen and were more simply analysed. Figure 1 shows the general appearance of a single layer. There was a faint axial periodicity at 28.5 A, which was stronger at irregular multiples of 28.5 A (3 and 4 times were most common), and fine striations were also seen at about 3° to the tube axis. Low angle electron diffraction patterns (not shown) and optical diffraction patterns (Fig. 2) from these layers showed a complex meridian (as a result of the irregular nature of the repeat along the tube axis) which showed a clear maximum at 28.5 A, consistent with the basic subunit spacing.

Differentiation Processes of the Ocellar Retina of the Honeybee (Apis Mellifera L.)

1990 ◽  
Vol 48 (3) ◽  
pp. 430-431
Author(s):  
Maria Anna Pabst
Keyword(s):  
Apis Mellifera ◽  
Distal Part ◽  
Cell Layer ◽  
Single Layer ◽  
Photoreceptor Cells ◽  
Distal Segment ◽  
Compound Eyes ◽  
Thin Sections ◽  
Ultrastructural Studies ◽  
Adult Worker

In addition to the compound eyes, honeybees have three dorsal ocelli on the vertex of the head. Each ocellus has about 800 elongated photoreceptor cells. They are paired and the distal segment of each pair bears densely packed microvilli forming together a platelike fused rhabdom. Beneath a common cuticular lens a single layer of corneagenous cells is present.Ultrastructural studies were made of the retina of praepupae, different pupal stages and adult worker bees by thin sections and freeze-etch preparations. In praepupae the ocellar anlage consists of a conical group of epidermal cells that differentiate to photoreceptor cells, glial cells and corneagenous cells. Some photoreceptor cells are already paired and show disarrayed microvilli with circularly ordered filaments inside. In ocelli of 2-day-old pupae, when a retinogenous and a lentinogenous cell layer can be clearly distinguished, cell membranes of the distal part of two photoreceptor cells begin to interdigitate with each other and so start to form the definitive microvilli. At the beginning the microvilli often occupy the whole width of the developing rhabdom (Fig. 1).

Characterization of a monolayer graphitic structure

1994 ◽  
Vol 52 ◽  
pp. 760-761
Author(s):  
X. Lin ◽  
X. K. Wang ◽  
V. P. Dravid ◽  
J. B. Ketterson ◽  
R. P. H. Chang
Keyword(s):  
Three Dimensional ◽  
Single Layer ◽  
Synthesis Process ◽  
Graphitic Structure ◽  
Positive Gaussian Curvature ◽  
Graphitic Sheet ◽  
Structural And Electronic Properties ◽  
New Material ◽  
Hexagonal Network

For small curvatures of a graphitic sheet, carbon atoms can maintain their preferred sp2 bonding while allowing the sheet to have various three-dimensional geometries, which may have exotic structural and electronic properties. In addition the fivefold rings will lead to a positive Gaussian curvature in the hexagonal network, and the sevenfold rings cause a negative one. By combining these sevenfold and fivefold rings with sixfold rings, it is possible to construct complicated carbon sp2 networks. Because it is much easier to introduce pentagons and heptagons into the single-layer hexagonal network than into the multilayer network, the complicated morphologies would be more common in the single-layer graphite structures. In this contribution, we report the observation and characterization of a new material of monolayer graphitic structure by electron diffraction, HREM, EELS.The synthesis process used in this study is reported early. We utilized a composite anode of graphite and copper for arc evaporation in helium.

Multislice calculations of RHEED patterns from vicinal Si (001)

1993 ◽  
Vol 51 ◽  
pp. 1000-1001
Author(s):  
Scott Lordi
Keyword(s):  
Misorientation Angle ◽  
Incident Angle ◽  
Incident Beam ◽  
Experimental Results ◽  
Bragg Condition ◽  
Vicinal Surfaces ◽  
Kinematic Theory ◽  
Step Edges

Vicinal Si (001) surfaces are interesting because they are good substrates for the growth of III-V semiconductors. Spots in RHEED patterns from vicinal surfaces are split due to scattering from ordered step arrays and this splitting can be used to determine the misorientation angle, using kinematic arguments. Kinematic theory is generally regarded to be inadequate for the calculation of RHEED intensities; however, only a few dynamical RHEED simulations have been attempted for vicinal surfaces. The multislice formulation of Cowley and Moodie with a recently developed edge patching method was used to calculate RHEED patterns from vicinal Si (001) surfaces. The calculated patterns are qualitatively similar to published experimental results and the positions of the split spots quantitatively agree with kinematic calculations.RHEED patterns were calculated for unreconstructed (bulk terminated) Si (001) surfaces misoriented towards [110] ,with an energy of 15 keV, at an incident angle of 36.63 mrad ([004] bragg condition), and a beam azimuth of [110] (perpendicular to the step edges) and the incident beam pointed down the step staircase.

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