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60
Sep 22, 2013
09/13
by
Fabien Tran; Peter Blaha
texts
eye 60
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The implementation of screened hybrid functionals into the WIEN2k code, which is based on the LAPW basis set, is reported. The Hartree-Fock exchange energy and potential are screened by means of the Yukawa potential as proposed by Bylander and Kleinman [Phys. Rev. B 41, 7868 (1990)] for the calculation of the electronic structure of solids with the screened-exchange local density approximation. Details of the formalism, which is based on the method of Massidda, Posternak, and Baldereschi [Phys....
Source: http://arxiv.org/abs/1103.4466v2
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73
Sep 18, 2013
09/13
by
Fabien Tran; David Koller; Peter Blaha
texts
eye 73
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We present the results of calculations on bulk transition metals Rh, Pd, and Pt using the screened hybrid functional YS-PBE0 [F. Tran and P. Blaha, Phys. Rev. B \textbf{83}, 235118 (2011)]. The results for the equilibrium geometry are compared with those obtained from (semi)local functionals, namely, the local density approximation and the generalized gradient approximation PBE of Perdew \textit{et al}. [J. P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. \textbf{77}, 3865 (1996)]. It is...
Source: http://arxiv.org/abs/1209.6247v1
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7.0
Jun 29, 2018
06/18
by
Fabien Tran; Julia Stelzl; Peter Blaha
texts
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A large panel of old and recently proposed exchange-correlation functionals belonging to rungs 1 to 4 of Jacob's ladder of density functional theory are tested (with and without a dispersion correction term) for the calculation of the lattice constant, bulk modulus, and cohesive energy of solids. Particular attention will be paid to the functionals MGGA_MS2 [J. Sun et al., J. Chem. Phys. 138, 044113 (2013)], mBEEF [J. Wellendorff et al., J. Chem. Phys. 140, 144107 (2014)], and SCAN [J. Sun et...
Topics: Chemical Physics, Materials Science, Condensed Matter, Physics
Source: http://arxiv.org/abs/1603.01504
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43
Jul 20, 2013
07/13
by
David Koller; Peter Blaha; Fabien Tran
texts
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(Screened) hybrid functionals are being used more and more for solid-state calculations. Usually the fraction alpha of Hartree-Fock exchange is kept fixed during the calculation, however there is no single (universal) value for alpha which systematically leads to satisfying accuracy. Instead, one could use a property of the system under consideration to determine alpha and in this way the functional would be more flexible and potentially more accurate. Recently, it was proposed to use the...
Source: http://arxiv.org/abs/1304.4470v1
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41
Jul 20, 2013
07/13
by
Han Hsu; Peter Blaha; Renata M. Wentzcovitch
texts
eye 41
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With local density approximation + Hubbard $U$ (LDA+$U$) calculations, we show that the ferromagnetic (FM) insulating state observed in tensile-strained LaCoO$_3$ epitaxial thin films is most likely a mixture of low-spin (LS) and high-spin (HS) Co, namely, a HS/LS mixture state. Compared with other FM states, including the intermediate-spin (IS) state (\textit{metallic} within LDA+$U$), which consists of IS Co only, and the insulating IS/LS mixture state, the HS/LS state is the most favorable...
Source: http://arxiv.org/abs/1203.1861v1
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11
Jun 26, 2018
06/18
by
Fabien Tran; Markus Betzinger; Peter Blaha; Stefan Blügel
texts
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The exact-exchange (EXX) potential, which is obtained by solving the optimized-effective potential (OEP) equation, is compared to various approximate semilocal exchange potentials for a set of selected solids (C, Si, BN, MgO, Cu$_{2}$O, and NiO). This is done in the framework of the linearized augmented plane-wave method, which allows for a very accurate all-electron solution of electronic structure problems in solids. In order to assess the ability of the semilocal potentials to approximate...
Topics: Materials Science, Strongly Correlated Electrons, Condensed Matter
Source: http://arxiv.org/abs/1501.07105
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6.0
Jun 29, 2018
06/18
by
Fabien Tran; Peter Blaha; Markus Betzinger; Stefan Blügel
texts
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In the search for an accurate and computationally efficient approximation to the exact exchange potential of Kohn-Sham density functional theory, we recently compared various semilocal exchange potentials to the exact one [F. Tran et al., Phys. Rev. B 91, 165121 (2015)]. It was concluded that the Becke-Johnson (BJ) potential is a very good starting point, but requires the use of empirical parameters to obtain good agreement with the exact exchange potential. In the present work, we extend the...
Topics: Materials Science, Condensed Matter, Strongly Correlated Electrons
Source: http://arxiv.org/abs/1608.08415
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39
Sep 22, 2013
09/13
by
Han Hsu; Peter Blaha; Matteo Cococcioni; Renata M. Wentzcovitch
texts
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Using density functional theory plus Hubbard $U$ calculations, we show that the ground state of (Mg,Fe)(Si,Fe)O$_3$ perovskite, a major mineral phase in the Earth's lower mantle, has high-spin ferric iron ($S=5/2$) at both the dodecahedral (A) and octahedral (B) site. As the pressure increases, the B-site iron undergoes a spin-state crossover to the low-spin state ($S=1/2$), while the A-site iron remains in the high-spin state. Our calculation shows that the B-site spin-state crossover in the...
Source: http://arxiv.org/abs/1101.3819v2
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7.0
Jun 29, 2018
06/18
by
Saleem Ayaz Khan; Jan Minár; Hubert Ebert; Peter Blaha; Ondřej Šipr
texts
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Local aspects of magnetism of disordered FePt are investigated by ab initio fully relativistic full potential calculations, employing the supercell approach and the coherent potential approximation (CPA). The focus is on trends of the spin and orbital magnetic moments with chemical composition and with bond lengths around the Fe and Pt atoms. A small but distinct difference between average magnetic moments obtained when using the supercells and when relying on the CPA is identified and linked...
Topics: Materials Science, Condensed Matter
Source: http://arxiv.org/abs/1610.04474
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3.0
Jun 29, 2018
06/18
by
Saleem Ayaz Khan; Peter Blaha; Hubert Ebert; Jan Minár; Ondřej Šipr
texts
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To get a reliable ab-initio value for the magneto-crystalline anisotropy (MCA) energy of FePt, we employ the full-potential linearized augmented plane wave (FLAPW) method and the full-potential Korringa-Kohn-Rostoker (KKR) Green function method. The MCA energies calculated by both methods are in a good agreement with each other. As the calculated MCA energy significantly differs from experiment, it is clear that many-body effects beyond the local density approximation are essential. It is not...
Topics: Materials Science, Condensed Matter
Source: http://arxiv.org/abs/1604.00176
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90
Sep 21, 2013
09/13
by
Elias Assmann; Peter Blaha; Robert Laskowski; Karsten Held; Satoshi Okamoto; Giorgio Sangiovanni
texts
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We propose an unexplored class of absorbing materials for high-efficiency solar cells: heterostructures of transition-metal oxides. In particular, LaVO_3 grown on SrTiO_3 has a direct band gap ~1.1 eV in the optimal range as well as an internal potential gradient, which can greatly help to separate the photo-generated electron-hole pairs. Furthermore, oxide heterostructures afford the flexibility to combine LaVO_3 with other materials such as LaFeO_3 in order to achieve even higher efficiencies...
Source: http://arxiv.org/abs/1301.1314v3
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175
Jul 20, 2013
07/13
by
Max Petersen; Frank Wagner; Lars Hufnagel; Matthias Scheffler; Peter Blaha; Karlheinz Schwarz
texts
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The full-potential linearized augmented-plane wave (FP-LAPW) method is well known to enable most accurate calculations of the electronic structure and magnetic properties of crystals and surfaces. The implementation of atomic forces has greatly increased it's applicability, but it is still generally believed that FP-LAPW calculations require substantial higher computational effort compared to the pseudopotential plane wave (PPW) based methods. In the present paper we analyse the FP-LAPW method...
Source: http://arxiv.org/abs/cond-mat/9902277v1
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68
Sep 22, 2013
09/13
by
Lars Winterfeld; Luis A. Agapito; Jin Li; Nicholas Kioussis; Peter Blaha; Yong P. Chen
texts
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Using ab initio electronic structure calculations we investigate the change of the band structure and the nu_0 topological invariant in HgSe (non-centrosymmetric system) under two different type of uniaxial strain along the [001] and [110] directions, respectively. Both compressive [001] and [110] strain leads to the opening of a (crystal field) band gap (with a maximum value of about 37 meV) in the vicinity of Gamma, and the concomitant formation of a camel-back- (inverse camel-back-) shape...
Source: http://arxiv.org/abs/1302.4125v1
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45
Sep 17, 2013
09/13
by
Philipp Haas; Fabien Tran; Peter Blaha; Luana S. Pedroza; Antonio J. R. da Silva; Mariana M. Odashima; Klaus Capelle
texts
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Eleven density functionals are compared with regard to their performance for the lattice constants of solids. We consider standard functionals, such as the local-density approximation and the Perdew-Burke-Ernzerhof (PBE) generalized-gradient approximation (GGA), as well as variations of PBE GGA, such as PBEsol and similar functionals, PBE-type functionals employing a tighter Lieb-Oxford bound, and combinations thereof. Several of these variations are proposed here for the first time. On a test...
Source: http://arxiv.org/abs/1003.2530v1
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3.0
Jun 30, 2018
06/18
by
Philip J. W. Moll; Jakob Kanter; Ross D. McDonald; Fedor F. Balakirev; Peter Blaha; Karlheinz Schwarz; Zbigniew Bukowski; Nikolai D. Zhigadlo; Sergiy Katrych; Kurt Mattenberger; Janusz Karpinski; Bertram Batlogg
texts
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We have studied the angular dependent de Haas-van Alphen oscillations of LaRu$_2$P$_2$ using magnetic torque in pulsed magnetic fields up to 60T. The observed oscillation frequencies are in excellent agreement with the geometry of the calculated Fermi surface. The temperature dependence of the oscillation amplitudes reveals effective masses m*($\alpha$)=0.71 and m*($\beta$)=0.99 m$_e$, which are enhanced over the calculated band mass by $\lambda^{cyc}$ of 0.8. We find a similar enhancement...
Topics: Superconductivity, Condensed Matter
Source: http://arxiv.org/abs/1410.7741
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50
Jun 30, 2011
06/11
by
Peter Blaha, GDMpro
movies
eye 50
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Live at the Connecticut Yankee April 2010
Topics: Cecil "Pnut" Daniels, Chris Zanardi, James Whiton, Eric Levy, Peter Blaha, gdmpro,...
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40
Jul 18, 2013
07/13
by
Peter Blaha GDMproductions
movies
eye 40
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Donna Jean and The Tricksters Live at KPFA
Topics: Jam band, Grateful dead, blues, Rock & Roll
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184
Aug 7, 2011
08/11
by
Peter Blaha, GDMpro
movies
eye 184
favorite 0
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Live Concert from November 29th 2009
Topics: Tommy Thomsen, gdmpro, peter blaha, gdmproductions
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302
Dec 25, 2011
12/11
by
Peter Blaha, gdmproductions
movies
eye 302
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2nd Set from a Live show in Pacifica, Ca in 2005
( 1 reviews )
Topics: David Nelson, Barry Sless, Mookie Siegel, GDMpro
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107
Aug 7, 2011
08/11
by
Peter Blaha, GDMpro
movies
eye 107
favorite 0
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Live Concert from November 29th 2009 Sonoma Valley
Topics: Tommy Thomsen, gdmpro, peter blaha, gdmproductions
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316
Sep 18, 2012
09/12
by
Peter Blaha, GDMproductions
movies
eye 316
favorite 0
comment 1
While I still can, switch me back to the old player Live at the Sweetwater Sep.20th 2007 one of the last shows at the original location. Video produced by GDMproductions: http://gdmpro.de/
favoritefavoritefavoritefavoritefavorite ( 1 reviews )
Topics: Grateful dead, Blues Guitar "Bob Weir (Singer)" Band Jam "Jam Band (Musical...
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280
Sep 18, 2012
09/12
by
Peter Blaha, GDMproductions
movies
eye 280
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Live at the Sweetwater Sep.20th 2007 one of the last shows at the original location. Video produced by GDMproductions: http://gdmpro.de/
Topics: Grateful dead, Blues Guitar "Bob Weir (Singer)" Band Jam "Jam Band (Musical...
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50
Jul 18, 2013
07/13
by
Peter Blaha, GDMproductions
movies
eye 50
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Tommy Thomsen, Live at Little Swiss
Topics: Western swing, Rock & Roll, blues
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237
Jun 27, 2011
06/11
by
Peter Blaha, GDMpro
movies
eye 237
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Concert from Melvin Seals and his Band, The Melting Pot Live at the Independent in San Francisco, December 21st 2001 1st Set.
Topics: Melvin Seals, Scott Law, Chris Haugen, Peter Blaha, GDMpro, gdmproductions
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252
Oct 13, 2011
10/11
by
Peter Blaha, GDMpro
movies
eye 252
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live at the Ashkenaz in Berkeley May 27th 2010 Audio recorded by Bob Cogswell
favoritefavoritefavoritefavoritefavorite ( 1 reviews )
Topics: mark karan, peter blaha, gdmproductions, gdmpro, bob gross, JT Thomas, Joe Chirco, Wally Ingram,...
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33
Sep 18, 2012
09/12
by
Peter Blaha, GDMproductions
movies
eye 33
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Produced by http://gdmpro.de/ Fareed Haque From Garaj Mahal joining Five Eyed Hand @ Moes Alley Santa Cruz,CA 10.21.07
Topics: jazz, music, gdmpro
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41
Jul 18, 2013
07/13
by
Peter Blaha, GDMproductions
movies
eye 41
favorite 0
comment 0
Tommy Thomsen, Live at Little Swiss
Topics: Western swing, rock & roll, blues
