Kaya Kobayashi

Observation of current-induced bulk magnetization in elemental tellurium

The magnetoelectric effect in bulk matter is of growing interest both fundamentally and technologically. Since the beginning of the century, the magnetoelectric effect has been studied intensively in multiferroic materials. However, magnetoelectric phenomena in materials without any (anti-)ferroic order remain almost unexplored. Here we show the observation of a new class of bulk magnetoelectric effect, by revisiting elemental trigonal tellurium. We demonstrate that elemental tellurium, which is a nonmagnetic semiconductor, exhibits current-induced magnetization. This effect is attributed to spin splitting of the bulk band owing to the lack of inversion symmetry in trigonal tellurium. This finding highlights magnetoelectricity in bulk matter driven by moving electrons without any (anti-)ferroic order. Notably, current-induced magnetization generates a magnetic field that is not circular around but is parallel to the applied current; thus, this phenomenon opens a new area of magnetic field generation beyond Ampere’s law that may lead to industrial applications.Electrical control of magnetic response in bulk material without electric or magnetic order is rare and potentially attractive for high efficient spintronics. Here, the authors report magnetization in elemental tellurium driven purely by current without any (anti-)ferroic order.

A separation of the Pt 5d orbital and spin moments in a ferrimagnetic CrPt3 compound

Abstract Magnetic circular X-ray dichroism at the Pt L-edges has been recorded from ferrimagnetic CrPt 3 intermetallics. The dichroic spectrum has a positive sign at both edges, which suggests that Pt 5d moments originating from the orbital character are antiferromagnetically coupled with Cr3d moments.

Evolution of the remnant Fermi-surface state in the lightly doped correlated spin-orbit insulator Sr2-xLaxIrO4

Electronic structure has been studied in lightly electron doped correlated spin-orbit insulator Sr

Enhanced superconducting transition temperatures in the rocksalt-type superconductors In1−xSnxTe (x≤0.5)

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Pressure-induced superconductivity in AgxBi2-xSe3

IrO

Magnetic phase diagram of S r2-x L axIr O4 synthesized by mechanical alloying

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Unusual upper critical field behavior in Nb-doped bismuth selenides

by angle-resolved photoelectron spectroscopy. We have observed coexistence of the lower Hubbard band and the in-gap band, the momentum dependence of the latter traces that of the band calculations without on-site Coulomb repulsion. The in-gap state remained anisotropically gapped in all observed momentum area, forming a remnant Fermi surface state, evolving towards the Fermi energy by carrier doping. These experimental results show a striking similarity with those observed in deeply underdoped cuprates, suggesting the common nature of the nodal liquid states observed in both compounds.

The electronic structure of Ag1−xSn1+xSe2 (x = 0.0, 0.1, 0.2, 0.25 and 1.0)

We investigate superconductivity in In1−xSnxTe (x 0.5) synthesized at high pressures of up to 2 GPa and observe an enhancement of the superconducting transition temperature Tc for increasing tin concentration x. These compounds have not been accessible in rocksalt structure via conventional ambient pressure synthesis. While the lattice constant smoothly increases with x, Tc saturates around x = 0.4. Electronic structure calculations indicate that the Tc modulation is brought on by the change of the density of states in the vicinity of the Fermi energy [N (EF)]. However, differences between the calculated N (EF) and the observed electronic specific-heat coefficient indicate that the phonon dispersion plays an important role in the system and that the mechanism of superconductivity may not be the same in the entire doping range.