Giant valley-Zeeman coupling in the surface layer of an intercalated transition metal dichalcogenide.

Spin-valley locking is ubiquitous among transition metal dichalcogenides with local or global inversion asymmetry, in turn stabilizing properties such as Ising superconductivity, and opening routes towards 'valleytronics'. The underlying valley-spin splitting is set by spin-orbit coupling but can be tuned via the application of external magnetic fields or through proximity coupling. However, only modest changes have been realized to date. Here, we investigate the electronic structure of the V-intercalated transition metal dichalcogenide V1/3NbS2 using microscopic-area spatially resolved and angle-resolved photoemission spectroscopy. Our measurements and corresponding density functional theory calculations reveal that the bulk magnetic order induces a giant valley-selective Ising coupling exceeding 50 meV in the surface NbS2 layer, equivalent to application of a ~250 T magnetic field. This energy scale is of comparable magnitude to the intrinsic spin-orbit splittings, and indicates how coupling of local magnetic moments to itinerant states of a transition metal dichalcogenide monolayer provides a powerful route to controlling their valley-spin splittings.

Spin Dynamics and Unconventional Coulomb Phase in Nd_{2}Zr_{2}O_{7}.

We investigate the temperature dependence of the spin dynamics in the pyrochlore magnet Nd_{2}Zr_{2}O_{7} by neutron scattering experiments. At low temperature, this material undergoes a transition towards an "all-in-all-out" antiferromagnetic phase and the spin dynamics encompass a dispersionless mode, characterized by a dynamical spin ice structure factor. Unexpectedly, this mode is found to survive above T_{N}≈300 mK. Concomitantly, elastic correlations of the spin ice type develop. These are the signatures of a peculiar correlated paramagnetic phase which can be considered as a new example of Coulomb phase. Our observations near T_{N} do not reproduce the signatures expected for a Higgs transition, but show reminiscent features of the "all-in-all-out" order superimposed on a Coulomb phase.

Restoration of Five Digit Hand in Type III B & C Thumb Hypoplasia-A Game Changer in Surgical Management.

Background Hypoplasia of thumb is the second common congenital difference of the thumb, next only to duplication. It may occur as an isolated hand difference or as a part of radial longitudinal deficiency. In approximately 60% of these children, the radius shows hypoplasia. The incidence of thumb hypoplasia is one in 100,000 live births. In 50% of these children, the other hand will also have similar deficiency, although variable in severity. Hypoplasia of thumb has been classified into five major categories, according to the increasing severity of hypoplasia. Type III hypoplasia of thumb is characterized by skeletal hypoplasia involving the first metacarpal and carpometacarpal joint, absent intrinsic muscles and rudimentary extrinsic muscles. It was further subclassified into types A, B & C. Type III B, described by Manske and McCarroll, involves extensive deficiency of extrinsic and intrinsic musculature with aplasia of the metacarpal base. Type III C, described by Buck-Gramcko, has hypoplastic metacarpal head. Methods It is widely believed that reconstruction of Type III B & C hypoplastic thumb will not be functionally useful, and they are often included in the indications for pollicization in thumb hypoplasia. In India, we frequently come across parents, who are not willing to remove the hypoplastic digit. This forced us to find out a way to reconstruct the hypoplastic thumb into a functionally useful digit. We describe our surgical technique of reconstruction of hypoplastic thumbs and our experience in utilization of the technique in five children with Type III B & C hypoplasia of thumb. Carpometacarpal joint of thumb was reconstructed and stabilized with a toe phalangeal transfer in the first stage and an opponensplasty was done in the second stage to improve movement. Results In all the five operated children, our surgical technique yielded a stable thumb which was functional. The donor site morbidity was acceptable. The parents were satisfied with the appearance and functional improvement. Conclusion Surgical reconstruction of hypoplastic thumbs of Type III B & C is possible, and conversion of these poorly developed remnants into a useful digit by our surgical technique is a gamechanger in the management of thumb hypoplasia.

Time-Reversal Symmetry Breaking in Re-Based Superconductors.

To trace the origin of time-reversal symmetry breaking (TRSB) in Re-based superconductors, we performed comparative muon-spin rotation and relaxation (µSR) studies of superconducting noncentrosymmetric Re_{0.82}Nb_{0.18} (T_{c}=8.8 K) and centrosymmetric Re (T_{c}=2.7 K). In Re_{0.82}Nb_{0.18}, the low-temperature superfluid density and the electronic specific heat evidence a fully gapped superconducting state, whose enhanced gap magnitude and specific-heat discontinuity suggest a moderately strong electron-phonon coupling. In both Re_{0.82}Nb_{0.18} and pure Re, the spontaneous magnetic fields revealed by zero-field µSR below T_{c} indicate time-reversal symmetry breaking and thus unconventional superconductivity. The concomitant occurrence of TRSB in centrosymmetric Re and noncentrosymmetric ReT (T=transition metal), yet its preservation in the isostructural noncentrosymmetric superconductors Mg_{10}Ir_{19}B_{16} and Nb_{0.5}Os_{0.5}, strongly suggests that the local electronic structure of Re is crucial for understanding the TRSB superconducting state in Re and ReT. We discuss the superconducting order parameter symmetries that are compatible with the experimental observations.

Pauling Entropy, Metastability, and Equilibrium in Dy_{2}Ti_{2}O_{7} Spin Ice.

Determining the fate of the Pauling entropy in the classical spin ice material Dy_{2}Ti_{2}O_{7} with respect to the third law of thermodynamics has become an important test case for understanding the existence and stability of ice-rule states in general. The standard model of spin ice-the dipolar spin ice model-predicts an ordering transition at T≈0.15 K, but recent experiments by Pomaranski et al. suggest an entropy recovery over long timescales at temperatures as high as 0.5 K, much too high to be compatible with the theory. Using neutron scattering and specific heat measurements at low temperatures and with long timescales (0.35 K/10^{6} s and 0.5 K/10^{5} s, respectively) on several isotopically enriched samples, we find no evidence of a reduction of ice-rule correlations or spin entropy. High-resolution simulations of the neutron structure factor show that the spin correlations remain well described by the dipolar spin ice model at all temperatures. Furthermore, by careful consideration of hyperfine contributions, we conclude that the original entropy measurements of Ramirez et al. are, after all, essentially correct: The short-time relaxation method used in that study gives a reasonably accurate estimate of the equilibrium spin ice entropy due to a cancellation of contributions.

Quality Heterostructures from Two-Dimensional Crystals Unstable in Air by Their Assembly in Inert Atmosphere.

Many layered materials can be cleaved down to individual atomic planes, similar to graphene, but only a small minority of them are stable under ambient conditions. The rest react and decompose in air, which has severely hindered their investigation and potential applications. Here we introduce a remedial approach based on cleavage, transfer, alignment, and encapsulation of air-sensitive crystals, all inside a controlled inert atmosphere. To illustrate the technology, we choose two archetypal two-dimensional crystals that are of intense scientific interest but are unstable in air: black phosphorus and niobium diselenide. Our field-effect devices made from their monolayers are conductive and fully stable under ambient conditions, which is in contrast to the counterparts processed in air. NbSe2 remains superconducting down to the monolayer thickness. Starting with a trilayer, phosphorene devices reach sufficiently high mobilities to exhibit Landau quantization. The approach offers a venue to significantly expand the range of experimentally accessible two-dimensional crystals and their heterostructures.

Fluctuations and All-In-All-Out Ordering in Dipole-Octupole Nd(2)Zr(2)O(7).

By means of neutron scattering and magnetization measurements down to 90 mK, we determine the magnetic ground state of the spin-ice candidate Nd(2)Zr(2)O(7). We show that, despite ferromagnetic interactions, Nd(2)Zr(2)O(7) undergoes a transition around 285 mK towards an all-in-all-out antiferromagnetic state, with a strongly reduced ordered magnetic moment. We establish the (H,T) phase diagram in the three directions of the applied field and reveal a metamagnetic transition around 0.1 T, associated with an unexpected shape of the magnetization curves. We propose that this behavior results from the peculiar nature of the Nd^{3+} doublet, a dipolar-octupolar doublet, different from the standard Kramers doublet studied to date, thus revealing the importance of multipolar correlations in the properties of pyrochlore oxides.

Unconventional Superconductivity in La(7)Ir(3) Revealed by Muon Spin Relaxation: Introducing a New Family of Noncentrosymmetric Superconductor That Breaks Time-Reversal Symmetry.

The superconductivity of the noncentrosymmetric compound La(7)Ir(3) is investigated using muon spin rotation and relaxation. Zero-field measurements reveal the presence of spontaneous static or quasistatic magnetic fields below the superconducting transition temperature T(c)=2.25 K-a clear indication that the superconducting state breaks time-reversal symmetry. Furthermore, transverse-field rotation measurements suggest that the superconducting gap is isotropic and that the pairing symmetry of the superconducting electrons is predominantly s wave with an enhanced binding strength. The results indicate that the superconductivity in La(7)Ir(3) may be unconventional and paves the way for further studies of this family of materials.

Time-resolved photo and radio-luminescence studies demonstrate the possibility of using InGaN/GaN quantum wells as fast scintillators.

In the recent publication by Hospodková et al, the authors investigate III-N quantum well structures as potential fast scintillators (Hospodková et al 2014 Nanotechnology 25 455501). The InGaN/GaN quantum well structures are grown using metal organic vapour phase epitaxy on a sapphire substrate and the fast carrier decay times are characterized by time resolved photo and radioluminescence.

Palm-Print Pattern Matching Based on Features Using Rabin-Karp for Person Identification.

Palm-print based individual identification is regarded as an effectual method for identifying persons with high confidence. Palm-print with larger inner surface of hand contains many features such as principle lines, ridges, minutiae points, singular points, and textures. Feature based pattern matching has faced the challenge that the spatial positional variations occur between the training and test samples. To perform effective palm-print features matching, Rabin-Karp Palm-Print Pattern Matching (RPPM) method is proposed in this paper. With the objective of improving the accuracy of pattern matching, double hashing is employed in RPPM method. Multiple patterns of features are matched using the Aho-Corasick Multiple Feature matching procedure by locating the position of the features with finite set of bit values as an input text, improving the cumulative accuracy on hashing. Finally, a time efficient bit parallel ordering presents an efficient variation on matching the palm-print features of test and training samples with minimal time. Experiment is conducted on the factors such as pattern matching efficiency rate, time taken on multiple palm-print feature matching efficiency, and cumulative accuracy on hashing.

Detection of time-reversal symmetry breaking in the noncentrosymmetric superconductor Re6Zr using muon-spin spectroscopy.

We have investigated the superconducting state of the noncentrosymmetric compound Re6Zr using magnetization, heat capacity, and muon-spin relaxation or rotation (µSR) measurements. Re6Zr has a superconducting transition temperature, Tc=6.75±0.05 K. Transverse-field µSR experiments, used to probe the superfluid density, suggest an s-wave character for the superconducting gap. However, zero and longitudinal-field µSR data reveal the presence of spontaneous static magnetic fields below Tc indicating that time-reversal symmetry is broken in the superconducting state and an unconventional pairing mechanism. An analysis of the pairing symmetries identifies the ground states compatible with time-reversal symmetry breaking.

Phase transition and thermal expansion studies of alumina thin films prepared by reactive pulsed laser deposition.

Aluminium oxide (Al2O3) thin films were deposited on Si (100) substrates at an optimized oxygen partial pressure of 3 x 10(-3) mbar at room temperature by pulsed laser deposition (PLD). The films were characterized by high temperature X-ray diffraction (HTXRD), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The HTXRD pattern showed the cubic y-Al2O3 phase in the temperature range 300-973 K. At temperatures ≥ 1073 K, the δ and θ-phases of Al2O3 were observed. The mean linear thermal expansion coefficient and volume thermal expansion coefficient of γ-Al2O3 was found to be 12.66 x 10(-6) K(-1) and 38.87 x 10(-6) K(-1) in the temperature range 300 K-1073 K. The field emission scanning electron microscopy revealed a smooth and structureless morphology of the films deposited on Si (100). The atomic force microscopy study indicated the increased crystallinity and surface roughness of the films after annealing at high temperature.

Resonant soft-X-ray emission as a bulk probe of correlated electron behavior in metallic SrxCa1-xVO3.

The evolution of electron correlation in SrxCa1-xVO3 has been studied using a combination of bulk-sensitive resonant soft x-ray emission spectroscopy, surface-sensitive photoemission spectroscopy, and ab initio band structure calculations. We show that the effect of electron correlation is enhanced at the surface. Strong incoherent Hubbard subbands are found to lie ∼20% closer in energy to the coherent quasiparticle features in surface-sensitive photoemission spectroscopy measurements compared with those from bulk-sensitive resonant soft x-ray emission spectroscopy, and a ∼10% narrowing of the overall bandwidth at the surface is also observed.

Adherence of the rotating vortex lattice in the noncentrosymmetric superconductor Ru7B3to the London model.

The noncentrosymmetric superconductor Ru7B3has in previous studies demonstrated remarkably unusual behaviour in its vortex lattice (VL), where the nearest neighbour directions of the vortices dissociate from the crystal lattice and instead show a complex field-history dependence, and the VL rotates as the field is changed. In this study, we look at the VL form factor of Ru7B3during this field-history dependence, to check for deviations from established models, such as the London model. We find that the data is well described by the anisotropic London model, which is in accordance with theoretical predictions that the alterations to the structure of the vortices due to broken inversion symmetry should be small. From this, we also extract values for the penetration depth and coherence length.

First-order reorientation transition of the flux-line lattice in CaAlSi.

The flux-line lattice in CaAlSi has been studied by small-angle neutron scattering. A well-defined hexagonal flux-line lattice is seen just above H(c1) in an applied field of only 54 Oe. A 30° reorientation of this vortex lattice has been observed in a very low field of 200 Oe. This reorientation transition appears to be first-order and could be explained by nonlocal effects. The magnetic field dependence of the form factor is well-described by a single penetration depth of λ=1496(1) Å and a single coherence length of ξ=307(1) Å at 2 K. At 1.5 K, the penetration depth anisotropy is γ(λ)=2.7(1), with the field applied perpendicular to the c axis, and agrees with the coherence length anisotropy determined from critical field measurements.

Omega Flap Technique: Revisiting Conventional Wisdom.

Various surgical techniques have been described for the release of syndactylized fingers. In our experience, the omega flap technique, which includes a dorsal truncated flap and an anchor incision on the volar side, stands out as a good technique to release syndactyly. Incidentally, in symbrachydactyly also, the fused digits can be released using this technique. Despite this, we could find no reference in the recent years. We would like to stress the ease and importance of this technique, hoping many practicing hand surgeons will benefit from this. Our purpose was to revisit this technique and expose it to the younger generation of hand surgeons. We have operated on 20 cases of syndactyly of different types-simple, compound, and complex-and 5 cases of symbrachydactyly. In all cases, the omega flap on the dorsum and anchor incision on the volar aspect of the finger forming 2 lateral palmar flaps were used. The release of syndactyly was satisfactory in all patients. There was no flap necrosis. None of these cases have required secondary surgery because the primary releases were adequate. Release of syndactyly had been a problem for centuries. Awareness of the disability was insufficient in earlier days; currently, they seek early medical care. The release should be complete. These children must be able to achieve the form and function of the hand, and additionally precision to work. We believe that the use of omega flap and anchor flap is a good procedure for syndactyly release.

Toggle-like current-induced Bloch point dynamics of 3D skyrmion strings in a room temperature nanowire.

Research into practical applications of magnetic skyrmions, nanoscale solitons with interesting topological and transport properties, has traditionally focused on two dimensional (2D) thin-film systems. However, the recent observation of novel three dimensional (3D) skyrmion-like structures, such as hopfions, skyrmion strings (SkS), skyrmion bundles, and skyrmion braids, motivates the investigation of new designs, aiming to exploit the third spatial dimension for more compact and higher performance spintronic devices in 3D or curvilinear geometries. A crucial requirement of such device schemes is the control of the 3D magnetic structures via charge or spin currents, which has yet to be experimentally observed. In this work, we utilise real-space imaging to investigate the dynamics of a 3D SkS within a nanowire of Co8Zn9Mn3 at room temperature. Utilising single current pulses, we demonstrate current-induced nucleation of a single SkS, and a toggle-like positional switching of an individual Bloch point at the end of a SkS. The observations highlight the possibility to locally manipulate 3D topological spin textures, opening up a range of design concepts for future 3D spintronic devices.

Large tunable Rashba spin splitting of a two-dimensional electron gas in Bi2Se3.

We report a Rashba spin splitting of a two-dimensional electron gas in the topological insulator Bi(2)Se(3) from angle-resolved photoemission spectroscopy. We further demonstrate its electrostatic control, and show that spin splittings can be achieved which are at least an order-of-magnitude larger than in other semiconductors. Together these results show promise for the miniaturization of spintronic devices to the nanoscale and their operation at room temperature.

Investigation of the magnetic ground state of GaV4S8using powder neutron diffraction.

The magnetic ground state of polycrystalline Néel skyrmion hosting material GaV4S8has been investigated usingacsusceptibility and powder neutron diffraction. In the absence of an applied magnetic field GaV4S8undergoes a transition from a paramagnetic to a cycloidal state below 13 K and then to a ferromagnetic-like state below 6 K. With evidence fromacsusceptibility and powder neutron diffraction, we have identified the commensurate magnetic structure at 1.5 K, with ordered magnetic moments of 0.23(2) µBon the V1 sites and 0.22(1) µBon the V2 sites. These moments have ferromagnetic-like alignment but with a 39(8)° canting of the magnetic moments on the V2 sites away from the V4cluster. In the incommensurate magnetic phase that exists between 6 and 13 K, we provide a thorough and careful analysis of the cycloidal magnetic structure exhibited by this material using powder neutron diffraction.

Deriving the skyrmion Hall angle from skyrmion lattice dynamics.

Magnetic skyrmions are topologically non-trivial, swirling magnetization textures that form lattices in helimagnetic materials. These magnetic nanoparticles show promise as high efficiency next-generation information carriers, with dynamics that are governed by their topology. Among the many unusual properties of skyrmions is the tendency of their direction of motion to deviate from that of a driving force; the angle by which they diverge is a materials constant, known as the skyrmion Hall angle. In magnetic multilayer systems, where skyrmions often appear individually, not arranging themselves in a lattice, this deflection angle can be easily measured by tracing the real space motion of individual skyrmions. Here we describe a reciprocal space technique which can be used to determine the skyrmion Hall angle in the skyrmion lattice state, leveraging the properties of the skyrmion lattice under a shear drive. We demonstrate this procedure to yield a quantitative measurement of the skyrmion Hall angle in the room-temperature skyrmion system FeGe, shearing the skyrmion lattice with the magnetic field gradient generated by a single turn Oersted wire.