138 research outputs found
Gapped Nearly Free-Standing Graphene on an SiC(0001) Substrate Induced by Manganese Atoms
The electron band structure of manganese-adsorbed graphene on an SiC(0001)
substrate has been studied using angle-resolved photoemission spectroscopy.
Upon introducing manganese atoms, the conduction band of graphene completely
disappears and the valence band maximum is observed at 0.4 eV below Fermi
energy. At the same time, the slope of the valence band decreases, approaching
the electron band structure calculated using the local density approximation
method. While the former provides experimental evidence of the formation of
nearly free-standing graphene on an SiC substrate, concomitant with a
metal-to-insulator transition, the latter suggests that its electronic
correlations can be modified by foreign atoms. These results pave the way for
promising device applications using graphene that is semiconducting and charge
neutral.Comment: 16 pages, 3 figure
Charge-spin correlation in van der Waals antiferromagenet NiPS3
Strong charge-spin coupling is found in a layered transition-metal
trichalcogenide NiPS3, a van derWaals antiferromagnet, from our study of the
electronic structure using several experimental and theoretical tools:
spectroscopic ellipsometry, x-ray absorption and photoemission spectroscopy,
and density-functional calculations. NiPS3 displays an anomalous shift in the
optical spectral weight at the magnetic ordering temperature, reflecting a
strong coupling between the electronic and magnetic structures. X-ray
absorption, photoemission and optical spectra support a self-doped ground state
in NiPS3. Our work demonstrates that layered transition-metal trichalcogenide
magnets are a useful candidate for the study of correlated-electron physics in
two-dimensional magnetic material.Comment: 6 pages, 3 figur
Broken Kramers' degeneracy in altermagnetic MnTe
Altermagnetism is a newly identified fundamental class of magnetism with
vanishing net magnetization and time-reversal symmetry broken electronic
structure. Probing the unusual electronic structure with nonrelativistic spin
splitting would be a direct experimental verification of altermagnetic phase.
By combining high-quality film growth and angle-resolved
photoemission spectroscopy, we report the electronic structure of an
altermagnetic candidate, -MnTe. Temperature dependent study reveals the
lifting of Kramers{\textquoteright} degeneracy accompanied by a magnetic phase
transition at with spin splitting of up to ,
providing direct spectroscopic evidence for altermagnetism in MnTe
UKIRT Widefield Infrared Survey for Fe+
The United Kingdom Infrared Telescope (UKIRT)Widefield Infrared Survey for Fe+ (UWIFE) is a 180 deg2 imaging survey of the first Galactic quadrant (7° < l < 62° |b| <1°.5) that uses a narrow-band filter centred on the [Fe II] 1.644-μm emission line. The [Fe II] 1.644-μm emission is a good tracer of dense, shock-excited gas, and the survey will probe violent environments around stars: star-forming regions, evolved stars, and supernova remnants, among others. The UWIFE survey is designed to complement the existing UKIRTW idefield Infrared Survey for H2 (UWISH2). The survey will also complement existing broad-band surveys. The observed images have a nominal 5Ï? detection limit of 18.7 mag for point sources, with a median seeing of 0.83 arcsec. For extended sources, we estimate a surface brightness limit of 8.1 Ã? 10-20 W m-2 arcsec-2. In this paper, we present an overview and some preliminary results of this survey. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
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