575 research outputs found
Activation analysis of admixtures in certain semiconductive materials
The use of extractions and chromatographic operations to separate macrobases, and to divide elements into groups convenient for gamma-spectrometric analysis is discussed. Methods are described for the activation detection of some impurities in silicon, arsenic, thallium, and trichloromethylsilane, on the basis of the extraction properties of bis(2-chlorethyl ether) and dimethylbenzylalkylammonium chloride. A schematic diagram of the extraction separation of elements-admixture is presented showing the aqueous and organic phases. The content percentage of the various elements are given in tables
Compositional variation of thin PZT films near morphotropic phase boundary: experiment and simulation
The work was partly supported by the Ministry for Education and Science (Russian Federation) (Grant No 16.2811.2017/4.6) and RFBR (Grant No 16-02-00632)
Spin excitations of the correlated semiconductor FeSi probed by THz radiation
By direct measurements of the complex optical conductivity of
FeSi we have discovered a broad absorption peak centered at frequency
that develops at temperatures below 20 K.
This feature is caused by spin-polaronic states formed in the middle of the gap
in the electronic density of states. We observe the spin excitations between
the electronic levels split by the exchange field of . Spin
fluctuations are identified as the main factor determining the formation of the
spin polarons and the rich magnetic phase diagram of FeSi.Comment: 5 pages, 4 figure
Highly anisotropic energy gap in superconducting Ba(FeCo)As from optical conductivity measurements
We have measured the complex dynamical conductivity, , of superconducting Ba(FeCo)As ( K) at terahertz frequencies and temperatures 2 - 30 K. In the frequency
dependence of below , we observe clear signatures of the
superconducting energy gap opening. The temperature dependence of
demonstrates a pronounced coherence peak at frequencies below 15 cm (1.8
meV). The temperature dependence of the penetration depth, calculated from
, shows power-law behavior at the lowest temperatures. Analysis of
the conductivity data with a two-gap model, gives the smaller isotropic s-wave
gap of meV, while the larger gap is highly anisotropic with
possible nodes and its rms amplitude is meV. Overall, our
results are consistent with a two-band superconductor with an gap
symmetry.Comment: 6 pages, 4 figures, discussion on pair-barking scattering and
possible lifting of the nodes is adde
Optical conductivity of multifold fermions: the case of RhSi
We measured the reflectivity of the multifold semimetal RhSi in a frequency
range from 80 to 20000 cm (10 meV - 2.5 eV) at temperatures down to 10
K. The optical conductivity, calculated from the reflectivity, is dominated by
the free-carrier (Drude) contribution below 1000 cm (120 meV) and by
interband transitions at higher frequencies. The temperature-induced changes in
the spectra are generally weak: only the Drude bands narrow upon cooling, with
an unscreened plasma frequency that is constant with temperature at
approximately 1.4 eV, in agreement with a weak temperature dependence of the
free-carrier concentration determined by Hall measurements. The interband
portion of conductivity exhibits two linear-in-frequency regions below 5000
cm ( 600 meV), a broad flat maximum at around 6000 cm (750
meV), and a further increase starting around 10000 cm ( 1.2 eV).
We assign the linear behavior of the interband conductivity to transitions
between the linear bands near the band crossing points. Our findings are in
accord with the predictions for the low-energy conductivity behavior in
multifold semimetals and with earlier computations based on band structure
calculations for RhSi.Comment: 7 pages, supplemental material added, figures improve
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