Germanium is a widely used material for electronic and optoelectronic devices and recently it has become an important material for spintronics and quantum computing applications. Donor spins in ...silicon have been shown to support very long coherence times (T_{2}) when the host material is isotopically enriched to remove any magnetic nuclei. Germanium also has nonmagnetic isotopes so it is expected to support long T_{2}'s while offering some new properties. Compared to Si, Ge has a strong spin-orbit coupling, large electron wave function, high mobility, and highly anisotropic conduction band valleys which will all give rise to new physics. In this Letter, the first pulsed electron spin resonance measurements of T_{2} and the spin-lattice relaxation (T_{1}) times for ^{75}As and ^{31}P donors in natural and isotopically enriched germanium are presented. We compare samples with various levels of isotopic enrichment and find that spectral diffusion due to ^{73}Ge nuclear spins limits the coherence in samples with significant amounts of ^{73}Ge. For the most highly enriched samples, we find that T_{1} limits T_{2} to T_{2}=2T_{1}. We report an anisotropy in T_{1} and the ensemble linewidths for magnetic fields oriented along different crystal axes but do not resolve any angular dependence to the spectral-diffusion-limited T_{2} in samples with ^{73}Ge.
We report the realization of a new mult-band-gap semiconductor. Zn(1-y)Mn(y)OxTe1-x alloys have been synthesized using the combination of oxygen ion implantation and pulsed laser melting. ...Incorporation of small quantities of isovalent oxygen leads to the formation of a narrow, oxygen-derived band of extended states located within the band gap of the Zn(1-y)Mn(y)Te host. When only 1.3% of Te atoms are replaced with oxygen in a Zn0.88Mn0.12Te crystal the resulting band structure consists of two direct band gaps with interband transitions at approximately 1.77 and 2.7 eV. This remarkable modification of the band structure is well described by the band anticrossing model. With multiple band gaps that fall within the solar energy spectrum, Zn(1-y)Mn(y)OxTe1-x is a material perfectly satisfying the conditions for single-junction photovoltaics with the potential for power conversion efficiencies surpassing 50%.
Background model of the CUPID-0 experiment Azzolini, O.; Beeman, J. W.; Bellini, F. ...
The European physical journal. C, Particles and fields,
07/2019, Letnik:
79, Številka:
7
Journal Article
Recenzirano
Odprti dostop
CUPID-0 is the first large mass array of enriched Zn
82
Se scintillating low temperature calorimeters, operated at LNGS since 2017. During its first scientific runs, CUPID-0 collected an exposure of ...9.95 kg year. Thanks to the excellent rejection of
α
particles, we attained the lowest background ever measured with thermal detectors in the energy region where we search for the signature of
82
Se
neutrinoless double beta decay. In this work we develop a model to reconstruct the CUPID-0 background over the whole energy range of experimental data. We identify the background sources exploiting their distinctive signatures and we assess their extremely low contribution down to
∼
10
-
4
counts/(keV kg year) in the region of interest for
82
Se
neutrinoless double beta decay search. This result represents a crucial step towards the comprehension of the background in experiments based on scintillating calorimeters and in next generation projects such as CUPID.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We present the search for Lorentz violation in the double beta decay of 82Se with CUPID-0, using an exposure of 9.95 kg × yr. We found no evidence for the searched signal and set a limit on the ...isotropic components of the Lorentz violating coefficient of ... <4.1×10−6 GeV (90% credible interval). This results is obtained with a Bayesian analysis of the experimental data and fully includes the systematic uncertainties of the model. This is the first limit on ... obtained with a scintillating bolometer, showing the potentiality of this technique. (ProQuest: ... denotes formulae omitted.)
Debris Disks around Sun-like Stars Trilling, D. E; Bryden, G; Beichman, C. A ...
The Astrophysical journal,
02/2008, Letnik:
674, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We have observed nearly 200 FGK stars at 24 and 70 mu m with the Spitzer Space Telescope. We identify excess infrared emission, including a number of cases where the observed flux is more than 10 ...times brighter than the predicted photospheric flux, and interpret these signatures as evidence of debris disks in those systems. We combine this sample of FGK stars with similar published results to produce a sample of more than 350 main sequence AFGKM stars. The incidence of debris disks is 4.2 super(+) sub(-) super(2) sub(1) super(.) sub(.) super(0) sub(1)% at 24 mu m for a sample of 213 Sun-like (FG) stars and 16.4 super(+) sub(2) super(2) sub(.) super(.) sub(9) super(8-)% at 70 mu m for 225 Sun-like (FG) stars. We find that the excess rates for A, F, G, and K stars are statistically indistinguishable, but with a suggestion of decreasing excess rate toward the later spectral types; this may be an age effect. The lack of strong trend among FGK stars of comparable ages is surprising, given the factor of 50 change in stellar luminosity across this spectral range. We also find that the incidence of debris disks declines very slowly beyond ages of 1 billion years.
Abstract
Comfort (Ralco Agriculture; Marshall, MN) is a feed additive that contains essential oils and capsicum which are antioxidants and selectively antimicrobial. The objective of this study was ...to evaluate the influence of Comfort on growth, intramuscular fat (IMF) accretion, and ultrasound ribeye area (REAU) in Akaushi and Akaushi crossbred steers and heifers at time of weaning. Steers and heifers (body weight = 257 ± 26.8 kg; n = 56) were weaned on d 0 at the ranch where they were born (Flatonia, TX). On d 0 animals were weighed, ultrasound scanned, and allocated to treatment. Treatments were a negative control that received no Comfort and a Comfort treatment, received 0.23 kg∙animal-1∙day-1 top-dressed on the ration. An equal number of steers and heifers were allocated to each treatment. Average daily high temperature was 38º C. On d 50, animals were shipped to the West Texas A&M University research feedyard (Canyon, TX); weighed and ultrasound scanned upon arrival. Data reported are the difference between d 0 and d 50 measurements. Data were analyzed using treatment as the fixed effect and individual animal as the experimental unit. Statistical analysis used PROC MIXED in SAS 9.4. Animal final BW was not different between treatments (285 COMF vs. 282 kg control; P = 0.77). Animal average daily gain (ADG) tended to be greater in the Comfort cattle compared with the control (0.61 vs. 0.47 kg/d; P = 0.09). Percentage IMF was significantly different between Comfort and control animals (0.14 vs. -0.12 %; P = 0.02). Animal REAU was not different between the treatments (3.39 for Comfort vs. 3.73 cm2 for control; P = 0.83). Fat thickness was not different between Comfort (0.1397 cm) and control cattle (0.1497 cm; P = 0.74). Data collected in this trial indicate that Comfort increased ADG and fat percentage with minimal changes to fat thickness and REAU.
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