545 research outputs found
Zoology of domain walls in quasi-2D correlated charge density wave of 1T-TaS2
Domain walls in correlated charge density wave compounds such as 1T-TaS2 can
have distinct localized states which govern physical properties and
functionalities of emerging quantum phases. However, detailed atomic and
electronic structures of domain walls have largely been elusive. We identify
using scanning tunneling microscope and density functional theory calculations
the atomic and electronic structures for a plethora of discommensuration domain
walls in 1T-TaS2 quenched metastably with nanoscale domain wall networks. The
domain walls exhibit various in-gap states within the Mott gap but metallic
states appear in only particular types of domain walls. A systematic
understanding of the domain-wall electronic property requests not only the
electron counting but also including various intertwined interactions such as
structural relaxation, electron correlation, and charge transfer. This work
guides the domain wall engineering of the functionality in correlated van der
Waals materials.Comment: 7 pages, 4 figure
Mobile Kink Solitons in a Van der Waals Charge-Density-Wave Layer
Kinks, point-like geometrical defects along dislocations, domain walls, and
DNA, are stable and mobile, as solutions of a sine-Gordon wave equation. While
they are widely investigated for crystal deformations and domain wall motions,
electronic properties of individual kinks have received little attention. In
this work, electronically and topologically distinct kinks are discovered along
electronic domain walls in a correlated van der Waals insulator of
1-TaS. Mobile kinks and antikinks are identified as trapped by pinning
defects and imaged in scanning tunneling microscopy. Their atomic structures
and in-gap electronic states are unveiled, which are mapped approximately into
Su-Schrieffer-Heeger solitons. The twelve-fold degeneracy of the domain walls
in the present system guarantees an extraordinarily large number of distinct
kinks and antikinks to emerge. Such large degeneracy together with the robust
geometrical nature may be useful for handling multilevel information in van der
Waals materials architectures.Comment: 12 pages, 4 figure
Diffuse Alveolar Hemorrhage in a 39-year-old Woman: Unusual Initial Presentation of Microscopic Polyangiitis
Microscopic polyangiitis (MPA) is a necrotizing vasculitis involving the small vessels without granulomatous inflammation. Most MPA initially presents with renal involvement without pulmonary involvement. Isolated and initially presenting alveolar hemorrhage is very rare. The patient was a 39-year-old female with a progressive cough, dyspnea, and blood-tinged sputum for the previous 5 days. We determined that her condition was MPA though VATS lung biopsy and renal biopsy. After 2 months of steroid therapy, the chest lesions had improved. We report here a rare case of MPA with isolated and initial involvement of the lung with a review of the literature
Pseudogap and weak multifractality in disordered Mott charge-density-wave insulator
The competition, coexistence and cooperation of various orders in
low-dimensional materials like spin, charge, topological orders and
charge-density-wave has been one of the most intriguing issues in condensed
matter physics. In particular, layered transition metal dichalcogenides provide
an ideal platform for studying such an interplay with a notable case of
1-TaS featuring Mott-insulating ground state, charge-density-wave,
spin frustration and emerging superconductivity together. We investigated local
electronic states of Se-substituted 1-TaS by scanning tunneling
microscopy/spectroscopy (STM/STS), where superconductivity emerges from the
unique Mott-CDW state. Spatially resolved STS measurements reveal that an
apparent V-shape pseudogap forms at the Fermi Level (E), with the origin
of the electronic states splitting and transformation from the Mott states, and
the CDW gaps are largely preserved. The formation of the pseudogap has little
correlation to the variation of local Se concentration, but appears to be a
global characteristics. Furthermore, the correlation length of local density of
states (LDOS) diverges at the Fermi energy and decays rapidly at high energies.
The spatial correlation shows a power-law decay close to the Fermi energy. Our
statistics analysis of the LDOS indicates that our system exhibits weak
multifractal behavior of the wave functions. These findings strongly support a
correlated metallic state induced by disorder in our system, which provides an
new insight into the novel mechanism of emerging superconductivity in the
two-dimensional correlated electronic systems
Total Gastrectomy in Gastric Conduit Cancer
We report a very rare case of surgery on gastric conduit cancer. A 67-year-old male patient underwent esophagectomy and intrathoracic esophagogastrostomy for squamous cell carcinoma of the lower thoracic esophagus 27 months ago. Upon follow-up, a gastric carcinoma at the intra-abdominal part of the gastric conduit was found on an esophagogastroduodenoscopy. We performed total gastrectomy and esophagocolonojejunostomy in the manner of Roux-en-Y anastomosis. The postoperative course was not eventful and an esophagogram on the 10th postoperative day showed no leakage or stenosis of the passage. The patient was discharged on the 17th day with no complications
Kinkless electronic junction along one dimensional electronic channel
Here we report the formation of type-A and type-B electronic junctions
without any structural discontinuity along a well-defined 1-nm-wide
one-dimensional electronic channel within a van der Waals layer. We employ
scanning tunneling microscopy and spectroscopy techniques to investigate the
atomic and electronic structure along peculiar domain walls formed on the
charge-density-wave phase of 1T-TaS2. We find distinct kinds of abrupt
electronic junctions with discontinuities of the band gap along the domain
walls, which do not have any structural kinks and defects. Our
density-functional calculations reveal a novel mechanism of the electronic
junction formation; they are formed by a kinked domain wall in the layer
underneath through substantial electronic interlayer coupling. This work
demonstrates that the interlayer electronic coupling can be an effective
control knob over several-nanometer-scale electronic property of
two-dimensional atomic monolayers
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