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The recent research on multiferroics has provided solid evidence that the breaking of inversion symmetry by spin order can induce ferroelectric polarization P . This type of multiferroics, called spin-driven ferroelectrics, often show a gigantic change in P on application of a magnetic field B . However, their polarization (<~0.1 μC cm −2 ) is much smaller than that in conventional ferroelectrics (typically several to several tens of μC cm −2 ). Here we show that the application of external pressure to a representative spin-driven ferroelectric, TbMnO 3 , causes a flop of P and leads to the highest P (≈1.0 μC cm −2 ) among spin-driven ferroelectrics ever reported. We explain this behaviour in terms of a pressure-induced magnetoelectric phase transition, based on the results of density functional simulations. In the high-pressure phase, the application of B further enhances P over 1.8 μC cm −2 . This value is nearly an order of magnitude larger than those ever reported in spin-driven ferroelectrics. Multiferroics are promising for their simultaneous ferroelectricity and magnetism, although in some of the most promising compounds the ferroelectric polarization remains small. Here, the authors show that applying external pressure to the multiferroic TbMnO 3 leads to a high ferroelectric polarization.

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 WTe 2 have attracted considerable interest. Here we report angle- and spin-resolved photoemission spectroscopy of WTe 2 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 WTe 2 is not strictly two dimensional. Tungsten ditelluride is a semi-metallic two-dimensional material that has exhibited large magnetoresistance. Here, the authors use angle- and spin-resolved photoemission spectroscopy to investigate the band structure of this transition metal dichalcogenide and identify layer-dependent electronic behaviour.

Interfacial magnetoelectric coupling is a viable path to achieve electrical writing of magnetic information in spintronic devices. For the prototypical Fe/BaTiO 3 system, only tiny changes of the interfacial Fe magnetic moment upon reversal of the BaTiO 3 dielectric polarization have been predicted so far. Here, by using X-ray magnetic circular dichroism in combination with high-resolution electron microscopy and first principles calculations, we report on an undisclosed physical mechanism for interfacial magnetoelectric coupling in the Fe/BaTiO 3 system. At this interface, an ultrathin oxidized iron layer exists, whose magnetization can be electrically and reversibly switched on and off at room temperature by reversing the BaTiO 3 polarization. The suppression/recovery of interfacial ferromagnetism results from the asymmetric effect that ionic displacements in BaTiO 3 produces on the exchange coupling constants in the interfacial-oxidized Fe layer. The observed giant magnetoelectric response holds potential for optimizing interfacial magnetoelectric coupling in view of efficient, low-power spintronic devices. Interfacial magnetoelectric coupling could lead to a new generation of memory devices. Here, Bertacco and colleagues observe a large electric-field switchable magnetoelectric coupling effect in iron/barium titanate heterostructures, which is due to a thin oxidized iron layer.

Density functional calculations have been tremendously useful in understanding the microscopic origin of multiferroicity and in quantifying relevant properties in many multiferroics and magnetoelectrics. Here, we focus on a relatively new and promising compound, PbNiO3. The structural, electronic and magnetic properties of its two polymorphs, i.e. the orthorhombic structure with space group Pnma and the rhombohedral LiNbO3-type structure with space group R3c have been studied by using density functional calculations within DFT + U and hybrid functional schemes. Our data convey an accurate description of the pressure-induced phase transition from the rhombohedral to orthorhombic phase at a predicted critical pressure of 5 GPa in agreement with the measured value of 3 GPa. Both phases show the G-type antiferromagnetic configuration as a magnetic ground state, but differ in the spatial anisotropy associated with nearest-neighbor exchange couplings, which is strongly weakened in the rhombohedral LiNbO3-type phase. The predicted large ferroelectric polarization of the rhombohedral phase (Hao et al 2012 Phys. Rev. B 014116) has been re-explored and analyzed in detail using partial density of states, Born effective charge tensors, charge density difference, electron localization function analysis and distortion mode analysis. The asymmetric bonding between the Pb 6s and O 2p orbitals along the [111]-direction is responsible for the polar cationic displacement, giving rise to a predicted large ferroelectric polarization as high as ∼ 100 μC cm−2.

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.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.

Nature Communications 7, Article number: 10847 (2016); Published 29 February 2016; Updated 13 April 2016. This Article contains errors in the numbering of the references in the text. The third sentence of the second paragraph should only refer to reference 2, not references 2 and 3. The correct sentence is:

Since October 2007, 18 surgical procedures have been carried out on 13 patients who had undergone coronary artery stenting with drug-eluting stents in the preceding 12 months.

Background Urologists have not reached a consensus regarding the pre-, intra-, and postoperative management of patients taking antiplatelet agents. This study aimed to evaluate the clinical course of patients receiving antithrombotic monotherapy with acetylsalicylic acid (ASA) 100 mg who underwent transurethral resection of bladder cancer. Methods This study was designed to compare the surgical outcomes for 108 transurethral resections of bladder cancer performed for patients taking antiplatelet therapy and for 105 procedures performed for patients who had never taken antiplatelet agents before surgery. Antiaggregant therapy was maintained according to criteria evaluated by a urologist, surgeon, anesthesiologist, and cardiologist. Variables were described using the mean as the location index and using standard deviation as a dispersion index if continuous percentages were used elsewhere. Group comparisons were performed using the t test or the chi-square test for categorical data, and Fisher’s exact test was used where appropriate. Results The mean operative time for patients taking ASA was 31 min (range 10–65 min), whereas it was 26 min (range 5–60 min) for control subjects. The difference between pre- and postoperative hemoglobin values was −0.6 g/dl in the group receiving antiplatelet therapy and −0.8 g/dl in the control group ( p  = 0.0720). Transfusional support was required during four procedures performed for patients taking antiplatelet therapy and during two procedures for the control group ( p  = 0.242). No adverse cardiac events or anesthesia-related complications occurred. Three patients in the treatment group and two patients in the control group required reintervention to ensure hemostasis during the postoperative period. None of the patients in either group underwent rehospitalization for hematuria after leaving the hospital. Conclusion The current results suggest that continued use of anti-aggregant monotherapy does not increase the risk of overall bleeding or reintervention for patients undergoing transurethral resection of bladder neoplasms and that suspending aspirin before such a procedure is therefore unnecessary.