13,873 research outputs found
Polarization screening and induced carrier density at the interface of LaAlO overlayer on SrTiO (001)
We investigate the role of lattice polarization in determination of induced
carrier density at the -type interface of LaAlO overlayer on SrTiO
(001) by carrying out density-functional-theory calculations. When no oxygen
vacancy or defect is present, the magnitude of polarization screening in the
LaAlO layers is found to be correlated with the carrier charge induced at
the interface. For the interfaces with a few LaAlO layers, the induced
charge carrier is compensated by the electrostatic screening and consequently
its density remains far less than 0.5 electrons per unit cell.Comment: 4 pages, 4 figure
Applications of degree estimate for subalgebras
Let be a field of positive characteristic and be the free
algebra of rank two over . Based on the degree estimate done by Y.-C. Li and
J.-T. Yu, we extend the results of S.J. Gong and J.T. Yu's results: (1) An
element is a test element if and only if does not
belong to any proper retract of ; (2) Every endomorphism preserving the
automorphic orbit of a nonconstant element of is an automorphism; (3)
If there exists some injective endomorphism of such that
where , then is a coordinate. And
we reprove that all the automorphisms of are tame. Moreover, we also
give counterexamples for two conjectures established by Leonid Makar-Limanov,
V. Drensky and J.-T. Yu in the positive characteristic case.Comment: 12 page
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Worldwide genetic variation of the IGHV and TRBV immune receptor gene families in humans.
The immunoglobulin heavy variable (IGHV) and T cell beta variable (TRBV) loci are among the most complex and variable regions in the human genome. Generated through a process of gene duplication/deletion and diversification, these loci can vary extensively between individuals in copy number and contain genes that are highly similar, making their analysis technically challenging. Here, we present a comprehensive study of the functional gene segments in the IGHV and TRBV loci, quantifying their copy number and single-nucleotide variation in a globally diverse sample of 109 (IGHV) and 286 (TRBV) humans from over a 100 populations. We find that the IGHV and TRBV gene families exhibit starkly different patterns of variation. In addition to providing insight into the different evolutionary paths of the IGHV and TRBV loci, our results are also important to the adaptive immune repertoire sequencing community, where the lack of frequencies of common alleles and copy number variants is hampering existing analytical pipelines
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