941 research outputs found
Andreev Reflection without Fermi surface alignment in High T-Topological heterostructures
We address the controversy over the proximity effect between topological
materials and high T superconductors. Junctions are produced between
BiSrCaCuO and materials with different Fermi
surfaces (BiTe \& graphite). Both cases reveal tunneling spectra
consistent with Andreev reflection. This is confirmed by magnetic field that
shifts features via the Doppler effect. This is modeled with a single parameter
that accounts for tunneling into a screening supercurrent. Thus the tunneling
involves Cooper pairs crossing the heterostructure, showing the Fermi surface
mis-match does not hinder the ability to form transparent interfaces, which is
accounted for by the extended Brillouin zone and different lattice symmetries
Requirements specification and architecture design for internet-based control
The Internet is playing an important role not only in
information retrieving, but also in industrial processes
manipulation. This paper describes an approach to
writing requirements specification for Internet-based
control systems and to deriving architecture for this new
type of control systems according to the requirements
specification. Specification is described in terms of a
functional model and then extended into information
architecture. Distinct from the functional model, the
information architecture gives an indication to the
architecture of the Internet-based control systems. An
integrated-distributed architecture has been derived from
the functional model and the information architecture as a
case study
Remarks on Hawking radiation as tunneling from the BTZ black holes
Hawking radiation viewed as a semiclassical tunneling process from the event
horizon of the (2 + 1)-dimensional rotating BTZ black hole is carefully
reexamined by taking into account not only the energy conservation but also the
conservation of angular momentum when the effect of the emitted particle's
self-gravitation is incorporated. In contrast to previous analysis of this
issue in the literature, our result obtained here fits well to the
Kraus-Parikh-Wilczek's universal conclusion without any modification to the
Bekenstein-Hawking area-entropy formulae of the BTZ black hole.Comment: 12pages, no figure, use JHEP3.cls. Version better than published one
in JHE
Evidence for a New Excitation at the Interface Between a High-Tc Superconductor and a Topological Insulator
High-temperature superconductors exhibit a wide variety of novel excitations.
If contacted with a topological insulator, the lifting of spin rotation
symmetry in the surface states can lead to the emergence of unconventional
superconductivity and novel particles. In pursuit of this possibility, we
fabricated high critical-temperature (Tc ~ 85 K) superconductor/topological
insulator (Bi2Sr2CaCu2O8+delta/Bi2Te2Se) junctions. Below 75 K, a zero-bias
conductance peak (ZBCP) emerges in the differential conductance spectra of this
junction. The magnitude of the ZBCP is suppressed at the same rate for magnetic
fields applied parallel or perpendicular to the junction. Furthermore, it can
still be observed and does not split up to at least 8.5 T. The temperature and
magnetic field dependence of the excitation we observe appears to fall outside
the known paradigms for a ZBCP
Atomic-scale visualization of quasiparticle interference on a type-II Weyl semimetal surface
We combine quasiparticle interference simulation (theory) and atomic
resolution scanning tunneling spectro-microscopy (experiment) to visualize the
interference patterns on a type-II Weyl semimetal MoWTe for
the first time. Our simulation based on first-principles band topology
theoretically reveals the surface electron scattering behavior. We identify the
topological Fermi arc states and reveal the scattering properties of the
surface states in MoWTe. In addition, our result reveals
an experimental signature of the topology via the interconnectivity of bulk and
surface states, which is essential for understanding the unusual nature of this
material.Comment: To appear in Phys. Rev. Let
Ground-based remote sensing cloud detection using dual pyramid network and encoder–decoder constraint
Many methods for ground-based remote sensing cloud detection learn representation features using the encoder–decoder structure. However, they only consider the information from single scale, which leads to incomplete feature extraction. In this article, we propose a novel deep network named dual pyramid network (DPNet) for ground-based remote sensing cloud detection, which possesses an encoder–decoder structure with dual pyramid pooling module (DPPM). Specifically, we process the feature maps of different scales in the encoder through dual pyramid pooling. Then, we fuse the outputs of the dual pyramid pooling in the same pyramid level using the attention fusion. Furthermore, we propose the encoder–decoder constraint (EDC) to relieve information loss in the process of encoding and decoding. It constrains the values and the gradients of probability maps from the encoder and the decoder to be consistent. Since the number of cloud images in the publicly available databases for ground-based remote sensing cloud detection is limited, we release the TJNU Large-scale Cloud Detection Database (TLCDD) that is the largest database in this field. We conduct a series of experiments on TLCDD, and the experimental results verify the effectiveness of the proposed method
Mirror protected Dirac fermions on a Weyl semimetal NbP surface
The first Weyl semimetal was recently discovered in the NbP class of
compounds. Although the topology of these novel materials has been identified,
the surface properties are not yet fully understood. By means of scanning
tunneling spectroscopy, we find that NbPs (001) surface hosts a pair of Dirac
cones protected by mirror symmetry. Through our high resolution spectroscopic
measurements, we resolve the quantum interference patterns arising from these
novel Dirac fermions, and reveal their electronic structure, including the
linear dispersions. Our data, in agreement with our theoretical calculations,
uncover further interesting features of the Weyl semimetal NbPs already exotic
surface. Moreover, we discuss the similarities and distinctions between the
Dirac fermions here and those in topological crystalline insulators in terms of
symmetry protection and topology
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