2,006 research outputs found
Observation of Modulated Quadrupolar Structures in PrPb3
Neutron diffraction measurements have been performed on the cubic compound
PrPb3 in a [001] magnetic field to examine the quadrupolar ordering.
Antiferromagnetic components with q=(1/2+-d 1/2 0), (1/2 1/2+-d 0) (d~1/8) are
observed below the transition temperature TQ (0.4 K at H=0) whose amplitudes
vary linear with H and vanish at zero field, providing the first evidence for a
modulated quadrupolar phase. For H<1 T, a non-square modulated state persists
even below 100 mK suggesting quadrupole moments associated with a Gamma3
doublet ground state to be partially quenched by hybridization with conduction
electrons.Comment: Physical Review Letters, in press. 4 pages, 4 figure
Multiorbital analysis of the effects of uniaxial and hydrostatic pressure on in the single-layered cuprate superconductors
The origin of uniaxial and hydrostatic pressure effects on in the
single-layered cuprate superconductors is theoretically explored. A two-orbital
model, derived from first principles and analyzed with the fluctuation exchange
approximation gives axial-dependent pressure coefficients, , , with a hydrostatic response
for both La214 and Hg1201 cuprates, in qualitative
agreement with experiments. Physically, this is shown to come from a unified
picture in which higher is achieved with an "orbital distillation",
namely, the less the main band is hybridized with the
and orbitals higher the . Some implications for obtaining higher
materials are discussed.Comment: 6pages, 4 figure
Lattice Distortion and Octupole Ordering Model in CexLa1-xB6
Possible order parameters of the phase IV in CexLa1-xB6 are discussed with
special attention to the lattice distortion recently observed. A
\Gamma_{5u}-type octupole order with finite wave number is proposed as the
origin of the distortion along the [111] direction. The \Gamma_8 crystalline
electric field (CEF) level splits into three levels by a mean field with the
\Gamma_{5u} symmetry. The ground and highest singlets have the same quadrupole
moment, while the intermediate doublet has an opposite sign. It is shown that
any collinear order of \Gamma_{5u}-type octupole moment accompanies the
\Gamma_{5g}-type ferro-quadrupole order, and the coupling of the quadrupole
moment with the lattice induces the distortion. The cusp in the magnetization
at the phase transition is reproduced, but the internal magnetic field due to
the octupole moment is smaller than the observed one by an order of magnitude.Comment: 5 pages, 4 figures, submitted to J. Phys. Soc. Jp
Re-entrant hidden order at a metamagnetic quantum critical end point
Magnetization measurements of URu2Si2 in pulsed magnetic fields of 44 T
reveal that the hidden order phase is destroyed before appearing in the form of
a re-entrant phase between ~ 36 and 39 T. Evidence for conventional itinerant
electron metamagnetism at higher temperatures suggests that the re-entrant
phase is created in the vicinity of a quantum critical end point.Comment: 8 pages, including 3 figures (Physical Review Letters, in press) a
systematic error in the field calibration has been fixed since the original
submission of this manuscrip
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