5,400 research outputs found
Growth kinetics effects on self-assembled InAs/InP quantum dots
A systematic manipulation of the morphology and the optical emission
properties of MOVPE grown ensembles of InAs/InP quantum dots is demonstrated by
changing the growth kinetics parameters. Under non-equilibrium conditions of a
comparatively higher growth rate and low growth temperature, the quantum dot
density, their average size and hence the peak emission wavelength can be tuned
by changing efficiency of the surface diffusion (determined by the growth
temperature) relative to the growth flux. We further observe that the
distribution of quantum dot heights, for samples grown under varying
conditions, if normalized to the mean height, can be nearly collapsed onto a
single Gaussian curve.Comment: 2 figure
Evolution of superconducting order in Pr(OsRu)Sb
We report measurements of the magnetic penetration depth in single
crystals of Pr(OsRu)Sb down to 0.1 K. Both
and superfluid density exhibit an exponential behavior for the
0.4 samples, going from weak (=0.4,0.6), to moderate, coupling
(=0.8). For the 0.2 samples, both and vary as
at low temperatures, but is s-wave-like at intermediate to
high temperatures. Our data are consistent with a three-phase scenario, where a
fully-gapped phase at undergoes two transitions: first to an
unconventional phase at , then to a nodal low-
phase at , for small values of .Comment: Changed title, enlarged numbering in figures 5 pages, 4 figures, 1
tabl
Superconducting phase diagram of the filled skuterrudite PrOs4Sb12
We present new measurements of the specific heat of the heavy fermion
superconductor PrOs4Sb12, on a sample which exhibits two sharp distinct
anomalies at Tc1= 1.89K and Tc2= 1.72K. They are used to draw a precise
magnetic field-temperature superconducting phase diagram of PrOs4Sb12 down to
350 mK.
We discuss the superconducting phase diagram of PrOs4Sb12 and its possible
relation with an unconventional superconducting order parameter. We give a
detailed analysis of Hc2(T), which shows paramagnetic limitation (a support for
even parity pairing) and multiband effects
Anomalous Anisotropic Magnetoresistance in Heavy-Fermion PrFe4P12
We have investigated the anisotropy of the magnetoresistance in the Pr-based
HF compound PrFe4P12. The large anisotropy of effective mass and its strong
field dependence have been confirmed by resistivity measurements. Particularly
for H||[111], where the effective mass is most strongly enhanced, the non-Fermi
liquid behavior has been observed. Also, we have found the angular dependence
of the magnetoresistance sharply enhanced at H||[111], which is evidently
correlated with both the non-Fermi liquid behavior and the high-field ordered
state (B-phase).Comment: 3 pages, 3 figures. J. Phys. Soc. Jpn. Vol.77, No.8, in pres
Study of electro-absorption effects in 1300nm In(Ga)As/GaAs quantum dot materials
No abstract available
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