1,648 research outputs found
Topological phase transition and two dimensional topological insulators in Ge-based thin films
We discuss possible topological phase transitions in Ge-based thin films of
Ge(BiSb)Te as a function of layer thickness and Bi
concentration using the first principles density functional theory
framework. The bulk material is a topological insulator at = 1.0 with a
single Dirac cone surface state at the surface Brillouin zone center, whereas
it is a trivial insulator at = 0. Through a systematic examination of the
band topologies we predict that thin films of Ge(BiSb)Te
with = 0.6, 0.8 and 1.0 are candidates for two-dimensional (2D) topological
insulators, which would undergo a 2D topological phase transition as a function
of . A topological phase diagram for Ge(BiSb)Te thin
films is presented to help guide their experimental exploration.Comment: 7 pages, 5 figures, Accepted for publication in Physical Review B
(2012
Creatinium hydrogen oxalate
The crystal structure of the title compound, C4H10N3O2
+·C2HO4
−, is stabilized by N—H⋯O and O—H⋯O hydrogen bonds. The anions are connected by an O—H⋯O hydrogen bond, leading to C(5) chain extending along c axis. The cations are dimerized around the corners of the unit cell, leading to an R
2
2(14) ring motif. This leads to a cationic molecular aggregation at x = 0 or 1 and an anionic molecular aggregation at x = 1/2
Creatininium cinnamate
The crystal structure of the title compound (systematic name: 2-amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium 3-phenylprop-2-enoate), C4H8N3O+·C9H7O2
−, is stabilized by N—H⋯O hydrogen bonding. Cations are linked to anions to form ion pairs with an R
2
2(8) ring motif. These ion pairs are connected through a C
2
2(6) chain motif extending along the c axis of the unit cell. This crystal packing is characterized by hydrophobic layers at x ∼ 1/2 packed between hydrophilic layers at x ∼ 0
Creatininium 2-chloroacetate
In the title compound (systematic name: 2-amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium 2-chloroacetate), C4H8N3O+·C2H2ClO2
−, the molecular aggregations are stabilized through classical (N—H⋯O) and non-classical (C—H⋯O and C—H⋯N) hydrogen-bonding interactions. The cations are linked to the anions, forming ion pairs through two N—H⋯O bonds that produce characteristic R
2
2(8) ring motifs. These cation–anion pairs are connected through another N—H⋯O hydrogen bond, leading to an R
4
2(8) ring motif. Further weak C—H⋯N interactions link the molecules along the a axis, while other C—H⋯O interactions generate zigzag chains extending along b
"The Financial Requirements of Achieving Gender Equality and Women's Empowerment"
Although the Millennium Development Goals (MDGs) have been ratified in global and national forums, they have not yet been incorporated into operational planning within governments or international organizations. The weak link between the policies and the investments needed for their implementation is one barrier to progress. An assessment of the resources required is a critical first step in formulating and implementing strategies to achieve the MDGs. This is especially true for policies to promote gender equality and empower women. Although enough is known about such policies to implement them successfully, the costs of such interventions are not systematically calculated and integrated into country-level budgeting processes. Using country-level data, the paper estimates the costs of interventions aimed at promoting gender equality and women's empowerment in Bangladesh, Cambodia, Ghana, Tanzania, and Uganda. It then uses these estimates to calculate the costs of such interventions in other low-income countries. Finally, the paper projects the financing gap for interventions that aim directly at achieving gender equality, first for the five countries, and subsequently for all low-income countries.
Two quantum analogues of Fisher information from a large deviation viewpoint of quantum estimation
We discuss two quantum analogues of Fisher information, symmetric logarithmic
derivative (SLD) Fisher information and Kubo-Mori-Bogoljubov (KMB) Fisher
information from a large deviation viewpoint of quantum estimation and prove
that the former gives the true bound and the latter gives the bound of
consistent superefficient estimators. In another comparison, it is shown that
the difference between them is characterized by the change of the order of
limits.Comment: LaTeX with iopart.cls, iopart12.clo, iopams.st
Creatininium hydrogen maleate
In the title compound, C4H8N3O+·C4H3O4
−, the cations and anions are linked through N—H⋯O hydrogen bonds making a ionic pair with an R
2
2(8) ring motif. These ionic pairs are further connected through another N—H⋯O hydrogen bond, leading to an R
6
6(16) ring motif around the inversion centres of the unit cell. These approximately planar aggregates are further connected through weak van der Waals interactions in the unit cell. The anions have a characteristic intramolecular O—H⋯O hydrogen bond with a self-associated ring S(7) motif
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