29,163 research outputs found
Absence of electron-phonon-mediated superconductivity in hydrogen-intercalated nickelates
No full textA recent experiment [X. Ding et al., Nature (London) 615, 50 (2023)] indicates that superconductivity in nickelates is restricted to a narrow window of hydrogen concentration, 0.22 < x < 0.28 in Nd0.8Sr0.2NiO2Hx. This reported necessity of hydrogen suggests that it plays a crucial role for superconductivity, as it does in the vast field of hydride superconductors. Using density-functional theory and its extensions, we explore the effect of topotactic hydrogen on the electronic structure and phonon-mediated superconductivity in nickelate superconductors. Our calculations show that the electron-phonon coupling in hydrogen-intercalated nickelates is not strong enough to drive the electron pairing, and thus cannot explain the reported superconductivity
Adrian Caesar speaking at Alex Miller author: A Celebration, held at the National Library, Canberra, 30 October 2011 /
No full textTitle from information supplied by photographer.; Part of the collection: Alex Miller author: A Celebration, held at the National Library of Australia theatre, 30 October 2011.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
Weyl nodes in Ce3Bi4Pd3 revealed by dynamical mean-field theory
No full text<p>This repository contains code and data corresponding to the Publication:</p>
<p>"Weyl nodes in Ce3Bi4Pd3 revealed by dynamical mean-field theory" by M. Braß, J. M. Tomczak and Karsten Held published in Physical Review Research (2024) (preprint: https://arxiv.org/abs/2404.17425)</p>
<p>All data is licensed under Creative Commons Attribution Share Alike 4.0 International, all software is licensed under the MIT License.</p>
<p>Please refer to the README.txt files and contact us in case of questions.</p>
<p>The files allow you to</p>
<ul>
<li>perform the DFT bandstructure calculation of Ce3Bi4Pd3</li>
<li>construct the Tight-binding Hamiltonian</li>
<li>search for Weyl points in the DFT bands</li>
<li>perform the DMFT calculations</li>
<li>analytically continue DMFT Green's function and self-energy</li>
<li>obtain the k-dependent DMFT spectral function</li>
<li>construct the quasi particle Hamiltonian and find its Weyl points</li>
</ul>
<p>Software requirements:</p>
<ul>
<li>FPLO : https://www.fplo.de/</li>
<li>w2dynamics : https://github.com/w2dynamics/w2dynamics</li>
<li>OmegaMaxEnt : https://github.com/amstremblay/OmegaMaxEnt</li>
<li>TightBindingToolBox : https://github.com/martinbrass/TightBindingToolBox</li>
</ul>
Pb10−xCux(PO4)6O: a Mott or charge transfer insulator in need of further doping for (super)conductivity
No full textWe briefly review the status quo of research on the putative superconductor Pb9Cu(PO4)6O also known as LK-99. Further, we provideab initioderived tight-binding parameters for a two- and five-band model, and solve these in dynamical-mean-field theory. The interaction-to-bandwidth ratio makes LK-99 a Mott or charge transfer insulator. Electron or hole doping (which is different from substituting Pb by Cu and thus differs from LK-99) is required to make it metallic and potentially superconducting.</p
Models of Democracy
No full textThe first two editions of Models of Democracy have proven immensely popular among students and specialists worldwide. In a succinct and far-reaching analysis, David Held provides an introduction to central accounts of democracy from classical Greece to the present and a critical discussion of what democracy should mean today.
This new edition has been extensively revised and updated to take account of significant transformations in world politics, and a new chapter has been added on deliberative democracy which focuses not only on how citizen participation can be increased in politics, but also on how that participation can become more informed.
Like its predecessor, the third edition of Models of Democracy combines lucid exposition and clarity of expression with careful scholarship and originality, making it highly attractive to students and experts in the field. The third edition will prove essential reading for all those interested in politics, political theory and political philosophy.
A companion website to Models of Democracy provides lecturer and student resources; including a study guide, an interview with the author and links to develop the reader's understanding of the topics covered
Legal regulation of prices in Tanzania : an examination of the Regulation of Prices Act 1973 as a tool of social change and development
No full textDrawing mainly from the Tazanian experience this study
attempts to review the principal issues in the legal regulation of
prices, by identifying both the general and specific importance
of law in this respect. The position I shall present is that
legal control is both necessary and desirable for the welfare
and social development of the people. The key issue is whether
the market-place will perform its function satisfactory: Will
it produce socially desirable results? If it will not, why will
it not? And will legal regulation help to do the job a little
better?
In an attempt to answer some of these questions,
first of all, outline the basic issues raised by the study in
the first Chapter. Then I examine the general case for price
controls - the theory about the controls, the motives and reasons
for their imposition and the manner in which they are effected
in different economic systems. This is done in Chapter Two. Relying
most on the available literature on the regulatory process, this
Chapter also looks at the relationship between law and economic
regulation and concludes that the effectiveness of law depends
on the existence of a conducive socio-economic environment. In
Chapter Three I describe the past record of price control laws
in Tanzania. I conclude that despite the failure in the past,
the controls still constitute an important policy instrument
in the transition to socialism. In Chapters Four and Five I describe
the manner in which the current regulations are implemented and
the problems encountered. I conclude that the operational performance
of the controls is constrained by internal and external influences on the economic and political life of the country. In the concluding
Chapter I assess the impact of the controls: Do the controls
work? Do people buy goods at the controlled prices? Why today
the controls are almost popularly accepted as worthwhile? I conclude
that while there may be no measurable economic gains derived
by consumers, the controls have a stabilising effect on the social
and political front. In the final section I argue that the
future success of the legislation depends on creating a correspondence
between the economic structures and the control system. What
makes the controls ineffective is not so much defects in the
law but the contradictions between the orientation of and functioning
of the economic system and the ideological commitment
Similarities between the Hubbard and Periodic Anderson Models at Finite Temperatures
No full textSimilarities between the Hubbard and Periodic Anderson Models at Finite Temperatures / K. Held ... - In: Physical review letters. 85. 2000. S. 373-37
Similarities between the Hubbard and Periodic Anderson Models at Finite Temperatures
No full textSimilarities between the Hubbard and Periodic Anderson Models at Finite Temperatures / K. Held ... - In: Physical review letters. 85. 2000. S. 373-37
Introduction to light emitting diode technology and applications / Gilbert Held.
No full textIncludes index.engineering bookfair2015"An Auerbach book".xv, 170 pages
Weyl nodes in Ce3Bi4Pd3 revealed by dynamical mean-field theory
No full textThis repository contains code and data corresponding to the Publication: "Weyl nodes in Ce3Bi4Pd3 revealed by dynamical mean-field theory" by M. Braß, J. M. Tomczak and Karsten Held published in Physical Review Research (2024) (preprint: https://arxiv.org/abs/2404.17425) All data is licensed under Creative Commons Attribution Share Alike 4.0 International, all software is licensed under the MIT License. Please refer to the README.txt files and contact us in case of questions. The files allow you to perform the DFT bandstructure calculation of Ce3Bi4Pd3 construct the Tight-binding Hamiltonian search for Weyl points in the DFT bands perform the DMFT calculations analytically continue DMFT Green's function and self-energy obtain the k-dependent DMFT spectral function construct the quasi particle Hamiltonian and find its Weyl points Software requirements: FPLO : https://www.fplo.de/ w2dynamics : https://github.com/w2dynamics/w2dynamics OmegaMaxEnt : https://github.com/amstremblay/OmegaMaxEnt TightBindingToolBox : https://github.com/martinbrass/TightBindingToolBo
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