36 research outputs found
Understanding Race and Ethnicity in Cancer and CV Disease: COVID-19 and a Roadmap for Change.
Quantum oscillations in from an incommensurate -density wave order
We consider quantum oscillation experiments in
from the perspective of an incommensurate
Fermi surface reconstruction using an exact transfer matrix method and the
Pichard-Landauer formula for the conductivity. The specific density wave order
considered is a period-8 -density wave in which the current density is
unidirectionally modulated. The current modulation is also naturally
accompanied by a period-4 site charge modulation in the same direction, which
is consistent with recent magnetic resonance measurements. In principle Landau
theory also allows for a period-4 bond charge modulation, which is not
discussed, but should be simple to incorporate in the future. This scenario
leads to a natural, but not a unique, explanation of why only oscillations from
a single electron pocket is observed, and a hole pocket of roughly twice the
frequency as dictated by two-fold commensurate order, and the corresponding
Luttinger sum rule, is not observed. However, it is possible that even higher
magnetic fields will reveal a hole pocket of half the frequency of the electron
pocket or smaller. This may be at the borderline of achievable high field
measurements because at least a few complete oscillations have to be clearly
resolved.Comment: 8 pages, 7 figure
Enhanced electron correlations in the new binary stannide PdSn4: a homologue of the Dirac nodal arc semimetal PtSn4
The advent of nodal-line semi-metals, i.e. systems in which the conduction
and valence bands cross each other along a closed trajectory (line or loop)
inside the Brillouin zone, has opened up a new arena for the exploration of
topological condensed matter in which, due to a vanishing density of states
near the Fermi level, electron correlation effects may also play an important
role. In spite of this conceptual richness however, material realization of
nodal-line (loop) fermions is rare, with PbTaSe2, ZrSiS and PtSn4 the only
promising known candidates. Here we report the synthesis and physical
properties of a new compound PdSn4 that is isostructural with PtSn4 yet
possesses quasiparticles with significantly enhanced effective masses. In
addition, PdSn4 displays an unusual polar angular magnetoresistance which at a
certain field orientation, varies linearly with field up to 55 Tesla. Our study
suggests that, in association with its homologue PtSn4 whose low-lying
excitations were recently claimed to possess Dirac node arcs, PdSn4 may be a
promising candidate in the search for novel topological states with enhanced
correlation effects.Comment: 6 figures, 1 tabl
Phenomenology of the normal state in-plane transport properties of high- cuprates
In this article, I review progress towards an understanding of the normal
state (in-plane) transport properties of high- cuprates in the light of
recent developments in both spectroscopic and transport measurement techniques.
Against a backdrop of mounting evidence for anisotropic single-particle
lifetimes in cuprate superconductors, new results have emerged that advocate
similar momentum dependence in the transport decay rate ({\bf k}). In
addition, enhancement of the energy scale (up to the bare bandwidth) over which
spectroscopic information on the quasiparticle response can be obtained has led
to the discovery of new, unforeseen features that surprisingly, may have a
significant bearing on the transport properties at the dc limit. With these two
key developments in mind, I consider here whether all the ingredients necessary
for a complete phenomenological description of the anomalous normal state
transport properties of high- cuprates are now in place.Comment: 31 pages, 10 figure
Suppression of the structural phase transition in by large magnetic fields
The transition in CeLaTh is measured
as a function of applied magnetic field using both resistivity and
magnetization. The transition temperature decreases with
increasing magnetic field, reaching zero temperature at around 56 T. The
magnetic-field dependence of the transition temperature may be fitted using a
model that invokes the field and temperature dependence of the entropy of the
-electron moments of the phase, suggesting that the volume
collapse in Ce and its alloys is primarily driven by entropic considerations
Lifshitz quantum phase transitions and Fermi surface transformation with hole doping in high- superconductors
We study the doping evolution of the electronic structure in the normal phase
of high- cuprates. Electronic structure and Fermi surface of cuprates with
single CuO layer in the unit cell like LaSrCuO have been
calculated by the LDA+GTB method in the regime of strong electron correlations
(SEC) and compared to ARPES and quantum oscillations data. We have found two
critical concentrations, and , where the Fermi surface
topology changes. Following I.M. Lifshitz ideas of the quantum phase
transitions (QPT) of the 2.5-order we discuss the concentration dependence of
the low temperature thermodynamics. The behavior of the electronic specific
heat is similar to the Loram and Cooper
experimental data in the vicinity of .Comment: 8 pages, 4 figure
Import Substitution Industrialization [ISI]: An approach to Global Economic Sustainability
Globalisation has over the years brought about openness, thus creating an inextricable link among countries through various channels, including trade and investment. Consequently, there has been a substantial expansion in trade in goods and services and the flow of foreign direct investment between developed and developing countries. Even though, both have benefitted from this global openness, the balance of benefits is mainly tilted to developed countries, reinforced by the fact that developing countries have been importing more and exporting less to these countries – a reflection of the under-developed state of their industrial sector, which is evident in their export of mainly unrefined or primary products, with little or no value addition taking place. This gives attestation to the presence of an insignificant import substitution-oriented manufacturing activity in such countries, which have rendered them heavily reliant on imports for their survival – by extension making them highly susceptible to external risks and shocks.
This brought about the inception of ISI, which originated from as early as in the 1930s through into the 1960s in Latin America and some parts of Asia and Africa – a notion that was meant to incorporate three stages, namely ‘domestic production of previously imported non-durable consumer goods, extension of production to a wide-range of consumer durables and complex manufactured items and finally, exporting of manufactured goods, with the vision of diversifying to multiple range of items’ (Bussell,, n/d)
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Robust image analysis with sparse representation on quantized visual features
10.1109/TIP.2012.2219543IEEE Transactions on Image Processing223860-871IIPR
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Suppression of the γ-α structural phase transition in Ce 0.8La0.1Th0.1 by large magnetic fields
The γ-α transition in Ce0.8La0.1Th 0.1 is measured as a function of applied magnetic field using both resistivity and magnetization. The γ-α transition temperature decreases with increasing magnetic field, reaching zero temperature at around 56 T. The magnetic-field dependence of the transition temperature is quantitatively reproduced by a model that invokes the field and temperature dependence of the entropy of the 4f-electron moments of the γ phase. © 2005 IOP Publishing Ltd