BiOCuS: A new superconducting compound with oxypnictide - related structure

The discovery of about 50 K superconductivity in the tetragonal Fe-based pnictides has stimulated the search for superconductivity in a wide class of materials with similar structure. Copper forms compounds isostructural to LaOFeAs. Single phase BiOCuS can be prepared by a solid state reaction at temperature lower than 500 C from a mixture of Bi2O3, Bi2S3 and Cu2S. The samples have been characterized by means of EDX analysis, X-ray diffraction, magnetic and electrical measurements. The cell parameters are a = 3.8708 A, c = 8.565 A. Charge carrier doping can be realized either by F substitutions for O, or by Cu off-stoichiometry. The latter doping route leads to the occurrence of superconductivity below Tc = 5.8 K

STM microscopy of the CDW in 1T-TiSe2 in the presence of single atom defects

We present a detailed low temperature scanning tunneling microscopy study of the commensurate charge density wave (CDW) in 1$T$-TiSe$_2$ in the presence of single atom defects. We find no significant modification of the CDW lattice in single crystals with native defects concentrations where some bulk probes already measure substantial reductions in the CDW phase transition signature. Systematic analysis of STM micrographs combined with density functional theory modelling of atomic defect patterns indicate that the observed CDW modulation lies in the Se surface layer. The defect patterns clearly show there are no 2$H$-polytype inclusions in the CDW phase, as previously found at room temperature [Titov A.N. et al, Phys. Sol. State 53, 1073 (2011). They further provide an alternative explanation for the chiral Friedel oscillations recently reported in this compound [J. Ishioka et al., Phys. Rev. B 84, 245125, (2011)].Comment: 5 pages, 4 figure

Doping nature of native defects in 1T-TiSe2

The transition metal dichalcogenide 1T-TiSe2 is a quasi two-dimensional layered material with a charge density wave (CDW) transition temperature of TCDW 200 K. Self-doping effects for crystals grown at different temperatures introduce structural defects, modify the temperature dependent resistivity and strongly perturbate the CDW phase. Here we study the structural and doping nature of such native defects combining scanning tunneling microscopy/spectroscopy and ab initio calculations. The dominant native single atom dopants we identify in our single crystals are intercalated Ti atoms, Se vacancies and Se substitutions by residual iodine and oxygen.Comment: 5 pages, 3 figure

Rashba spin-splitting control at the surface of the topological insulator Bi2Se3

The electronic structure of Bi2Se3 is studied by angle-resolved photoemission and density functional theory. We show that the instability of the surface electronic properties, observed even in ultra-high-vacuum conditions, can be overcome via in-situ potassium deposition. In addition to accurately setting the carrier concentration, new Rashba-like spin-polarized states are induced, with a tunable, reversible, and highly stable spin splitting. Ab-initio slab calculations reveal that these Rashba state are derived from the 5QL quantum-well states. While the K-induced potential gradient enhances the spin splitting, this might be already present for pristine surfaces due to the symmetry breaking of the vacuum-solid interface.Comment: A high-resolution version can be found at http://www.physics.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Articles/BiSe_K.pd

Doping nature of native defects in 1T−TiSe₂

The transition-metal dichalcogenide 1T−TiSe₂is a quasi-two-dimensional layered material with a charge density wave (CDW) transition temperature of TCDW≈200  K. Self-doping effects for crystals grown at different temperatures introduce structural defects, modify the temperature-dependent resistivity, and strongly perturbate the CDW phase. Here, we study the structural and doping nature of such native defects combining scanning tunneling microscopy or spectroscopy and ab initio calculations. The dominant native single atom dopants we identify in our single crystals are intercalated Ti atoms, Se vacancies, and Se substitutions by residual iodine and oxygen

Radiopharmaceuticals for Pancreatic Cancer: A Review of Current Approaches and Future Directions

The poor prognosis of pancreatic cancer requires novel treatment options. This review examines the evolution of radiopharmaceuticals in the treatment of pancreatic cancer. Established strategies such as peptide receptor radionuclide therapy (PRRT) offer targeted and effective treatment, compared to conventional treatments. However, there are currently no radiopharmaceuticals approved for the treatment of pancreatic cancer in Europe, which requires further research and novel approaches. New radiopharmaceuticals including radiolabeled antibodies, peptides, and nanotechnological approaches are promising in addressing the challenges of pancreatic cancer therapy. These new agents may offer more specific targeting and potentially improve efficacy compared to traditional therapies. Further research is needed to optimize efficacy, address limitations, and explore the overall potential of these new strategies in the treatment of this aggressive and harmful pathology

Short-range phase coherence and origin of the 1T−TiSe21T-{\mathrm{TiSe}}_{2} charge density wave

The impact of variable Ti self-doping on the 1T−TiSe2 charge density wave (CDW) is studied by scanning tunneling microscopy. Supported by density functional theory, we show that agglomeration of intercalated-Ti atoms acts as preferential nucleation centers for the CDW that breaks up in phase-shifted CDW domains whose size directly depends on the intercalated-Ti concentration and which are separated by atomically sharp phase boundaries. The close relationship between the diminution of the CDW domain size and the disappearance of the anomalous peak in the temperature-dependent resistivity allows to draw a coherent picture of the 1T−TiSe2 CDW phase transition and its relation to excitons

Local resilience of the 1T\text{\ensuremath{-}}{\mathrm{TiSe}}_{2} charge density wave to Ti self-doping

In Ti-intercalated self-doped 1T−TiSe2 crystals, the charge density wave (CDW) superstructure induces two nonequivalent sites for Ti dopants. Recently, it has been shown that increasing Ti doping dramatically influences the CDW by breaking it into phase-shifted domains. Here, we report scanning tunneling microscopy and spectroscopy experiments that reveal a dopant-site dependence of the CDW gap. Supported by density functional theory, we demonstrate that the loss of the long-range phase coherence introduces an imbalance in the intercalated-Ti site distribution and restrains the CDW gap closure. This local resilient behavior of the 1T−TiSe2 CDW reveals an entangled mechanism between CDW, periodic lattice distortion, and induced nonequivalent defects

Halide Perovskites Films for Ionizing Radiation Detection: An Overview of Novel Solid-State Devices

Halide perovskites are a novel class of semiconductors that have attracted great interest in recent decades due to their peculiar properties of interest for optoelectronics. In fact, their use ranges from the field of sensors and light emitters to ionizing radiation detectors. Since 2015, ionizing radiation detectors exploiting perovskite films as active media have been developed. Recently, it has also been demonstrated that such devices can be suitable for medical and diagnostic applications. This review collects most of the recent and innovative publications regarding solid-state devices for the detection of X-rays, neutrons, and protons based on perovskite thin and thick films in order to show that this type of material can be used to design a new generation of devices and sensors. Thin and thick films of halide perovskites are indeed excellent candidates for low-cost and large-area device applications, where the film morphology allows the implementation on flexible devices, which is a cutting-edge topic in the sensor sector