Unveiling the Electronic Structure of Pseudotetragonal WO3 Thin Films.

WO3 is a 5d compound that undergoes several structural transitions in its bulk form. Its versatility is well-documented, with a wide range of applications, such as flexopiezoelectricity, electrochromism, gating-induced phase transitions, and its ability to improve the performance of Li-based batteries. The synthesis of WO3 thin films holds promise in stabilizing electronic phases for practical applications. However, despite its potential, the electronic structure of this material remains experimentally unexplored. Furthermore, its thermal instability limits its use in certain technological devices. Here, we employ tensile strain to stabilize WO3 thin films, which we call the pseudotetragonal phase, and investigate its electronic structure using a combination of photoelectron spectroscopy and density functional theory calculations. This study reveals the Fermiology of the system, notably identifying significant energy splittings between different orbital manifolds arising from atomic distortions. These splittings, along with the system's thermal stability, offer a potential avenue for controlling inter- and intraband scattering for electronic applications.

Dual pulsed laser deposition system for the growth of complex materials and heterostructures.

Here, we present an integrated ultra-high-vacuum (UHV) apparatus for the growth of complex materials and heterostructures. The specific growth technique is the Pulsed Laser Deposition (PLD) by means of a dual-laser source based on an excimer KrF ultraviolet and solid-state Nd:YAG infra-red lasers. By taking advantage of the two laser sources-both lasers can be independently used within the deposition chambers-a large number of different materials-ranging from oxides to metals, to selenides, and others-can be successfully grown in the form of thin films and heterostructures. All of the samples can be in situ transferred between the deposition chambers and the analysis chambers by using vessels and holders' manipulators. The apparatus also offers the possibility to transfer samples to remote instrumentation under UHV conditions by means of commercially available UHV-suitcases. The dual-PLD operates for in-house research as well as user facility in combination with the Advanced Photo-electric Effect beamline at the Elettra synchrotron radiation facility in Trieste and allows synchrotron-based photo-emission as well as x-ray absorption experiments on pristine films and heterostructures.

Author Correction: Layer-dependent quantum cooperation of electron and hole states in the anomalous semimetal WTe2.

This Article contains an error in the spelling of the author A. Yazdani, which is incorrectly given as A. Yadzani. The error has not been fixed in the original PDF and HTML versions of the Article.

Layer-dependent quantum cooperation of electron and hole states in the anomalous semimetal WTe2.

The behaviour of electrons and holes in a crystal lattice is a fundamental quantum phenomenon, accounting for a rich variety of material properties. Boosted by the remarkable electronic and physical properties of two-dimensional materials such as graphene and topological insulators, transition metal dichalcogenides have recently received renewed attention. In this context, the anomalous bulk properties of semimetallic WTe2 have attracted considerable interest. Here we report angle- and spin-resolved photoemission spectroscopy of WTe2 single crystals, through which we disentangle the role of W and Te atoms in the formation of the band structure and identify the interplay of charge, spin and orbital degrees of freedom. Supported by first-principles calculations and high-resolution surface topography, we reveal the existence of a layer-dependent behaviour. The balance of electron and hole states is found only when considering at least three Te-W-Te layers, showing that the behaviour of WTe2 is not strictly two dimensional.

Growth of ultrathin epitaxial Fe/MgO spin injector on (0, 0, 1) (Ga, Mn)As.

We have grown an ultrathin epitaxial Fe/MgO bilayer on (Ga, Mn)As by e-beam evaporation in UHV. The system structure has been investigated by high resolution transmission electron microscopy (TEM) experiments which show that the Fe and MgO films, covering completely the (Ga, Mn)As, grow with the epitaxial relationship Fe[100](001) [parallel] MgO[110](001) [parallel] (Ga,Mn)As[110](001). The magnetic reversal process, studied by the magneto-optical Kerr effect (MOKE) at room temperature, demonstrates that the iron is ferromagnetic and possesses a cubic anisotropy, confirming the epitaxy relationship found with TEM. Resistivity measurements across the barrier display a non-Ohmic behavior characterized by cubic conductance as a function of the applied voltage suggesting tunneling-dominated transport across the barrier.

Electron backscattering diffraction and X-ray diffraction studies of interface relationships in Sr3Ru2O7/Sr2RuO4 eutectic crystals.

Sr3Ru2O7/Sr2RuO4 eutectic system is investigated by electron backscattering diffraction (EBSD) and X-ray diffraction (XRD). The eutectic growth enables the solidification of the two phases in an ordered lamellar pattern extending along the growth direction, namely the b-axis direction. The eutectic material thus provides in the a-c plane two distinct interfaces having different microstructures with respect to the growth direction. Our analysis shows that, across the inplane c-axis direction (characterized by a poor lattice matching), the b-axis orientation is not constant at the individual interfaces, showing an orientation spread of about 5°. However, across the in-plane a-axis direction (characterized by a good lattice matching), the b-axis orientation does not change within a few tenths of degree (about 0.25°). Such information at nanoscale is also verified on a macroscopic level by standard XRD investigation.

An in vivo comparison of working length determination of two frequency-based electronic apex locators.

AIM: To compare in vivo the accuracy of two electronic apex locators (EALs) by means of digital radiographic imaging system. METHODOLOGY: Electronic working lengths of 831 canals were determined with the DentaPort ZX and Raypex 5 apex locators and confirmed radiographically. The radiographic images acquired with the aid of a digital radiographic imaging system (VisualiX eHD; Gendex Dental Systems, Des Plaines, IL, USA) were blindly analysed by two independent evaluators. The distance between the file tip and the radiographic apex was measured using dedicated software (VixWin Pro, Gendex Dental Systems, Des Plaines, IL, USA) and the mean distance achieved between different tooth type and EALs were compared statistically. Statistical analyses were performed using the t-test for independent samples and one-way anova with the null hypothesis set as 5%. Positive or negative values were recorded when the file tip was detected beyond or short of the radiographic apex, respectively. RESULTS: The mean distance between file tip and radiographic apex were -1.08 +/- 0.73 and -1.0 +/- 0.67 mm considering DentaPort ZX and Raypex 5 groups, respectively, with no significant differences (P > 0.05). No statistically significant differences were found amongst the same tooth type when comparing both groups (P > 0.05) or amongst different teeth type in the same group (P > 0.05). CONCLUSIONS: Within the limitations of this in vivo study, the DentaPort ZX and Raypex 5 were similar in terms of accuracy.

[Criteria of diagnostic evaluation and results of surgical treatment in chronic pancreatitis]. / Criteri di valutazione diagnostica e risultati del trattamento chirurgico della pancreatite cronica.

Correct diagnostic evaluation of chronic pancreatitis pictures must of necessity be directed to recognition of recurrent and stable forms and identification of the pathogenetic cause of the clinical forms. This objective seems to be achieved more than satisfactions by the diagnostic protocol employed personally, the first stages of which include X-ray of the abdomen for the identification of possible pancreatic calcification, ultrasonography and computed axial tomography for the analysis of organ's morphology and structure, intestinal absorption and pharmacodynamic tests of the papillary excretory complex for the evaluation of functional state of the pancreas. At a second time, this diagnostic protocol includes endoscopic pancreatography for the analysis of the excretory duct and identification of possible calcareous concretions in its lumen, and district angiography, for information on the extreme viscero-vascular implications and the possibility of coexistence of district portal hypertension pictures. The resulting information dominates therapeutic choices by indicating the usefulness of performing a papillo-sphincteroplasty to handle the biliary aetiology in recurrent forms and Wirsung septoplasty for ductal ostial stenoses. The choice of shunts and resections is confirmed to the stable forms, with the use of the former in the event of ductal dilatation and of the latter in the absence of this and in the presence of more or less marked gland fibrosis. Derivative procedures also control treatment of chronic post-pancreatitis pseudocyst, with a clear-cut prevalence of cysto-gastric shunts over all the other possibilities.(ABSTRACT TRUNCATED AT 250 WORDS)

[Endoscopic papillotomy today. Indications and results]. / La papillotomia endoscopia oggi. Indicazioni e risultati.

The therapeutic possibilities offered by endoscopic papillotomy have improved in comparison with the recent past by virtue of mounting experience and increasingly satisfactory results. The position of the surgeon in the face of this procedure is more serene and objective than those who concern themselves with the endoscopic method as such. In long-term personal experience, endoscopic papillotomy was indicated in 162 cases of biliary lithiasic pathology--associated and otherwise with Odditis--and angiocolitis, with and without the gall-bladder. The reference to endoscopic treatment was mainly confined to patients with associated pathologies, dependent and otherwise, that involved general or specific surgical risk, while evaluations of the lumen of the biliary excretory way, of the coexistence of more or less incisive biliary inflammation, of the age of the patient--all parameters to which are attributed special importance for the choice between derivative intervention and open papillotomy--do not possess particular significance for the endoscopic method. Results obtained and the low incidence of short and long-term morbility support the claim to absolute usefulness of the method when it is proposed on correct indications and carried out with expert technique.