journal
MENU ▼
Read by QxMD icon Read
search

Journal of Physics. Condensed Matter: An Institute of Physics Journal

journal
https://www.readbyqxmd.com/read/28441145/laser-induced-ultrafast-spin-current-pulses-a-thermodynamic-approach
#1
A Fognini, T U Michlmayr, A Vaterlaus, Y Acremann
The ultrafast demagnetization process allows for the generation of femtosecond spin current pulses. Here, we present a thermodynamic model of the spin current generation process, based on the chemical potential gradients as the driving force for the spin current. We demonstrate that the laser-induced spin current can be estimated by an easy to understand diffusion model.
April 25, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28441143/ultrafast-demagnetization-in-bulk-versus-thin-films-an-ab-initio-study
#2
K Krieger, P Elliott, T Müller, N Singh, J K Dewhurst, E K U Gross, S Sharma
We report ab initio simulations of the quantum dynamics of electronic charge and spins when subjected to intense laser pulses. By performing these purely electron-dynamics calculations for a thin film and for the bulk of Ni, we conclude that formation of surfaces has a dramatic influence of amplifying the laser induced demagnetization. The reason for this amplification is enhanced spin-currents on the surface of the thin films. We show that the underlying physics of demagnetization for bulk is dominated by spin-flips induced by spin-orbit coupling...
April 25, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28441142/magnetization-dynamics-in-magnonic-structures-with-different-geometries-interfaces-notches-and-waveguides
#3
M Mansurova, J von der Haar, J Panke, Jakob Walowski, Henning Ulrichs, M Münzenberg
The discovery of ultrafast magnetization dynamics 20 years ago has led to a broad variety of experimental techniques to explore phenomena in magnetic materials with high temporal resolution. In the current article we present a study dealing with broadband excitation of spin-wave packets at different magnonic crystal continuous magnetic film interfaces. Similar to protected conducting states on the surfaces of topological band insulators, these interfaces exhibit surface spin-wave modes that propagate out of the crystal into the continuous film...
April 25, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28441141/crystal-growth-and-stoichiometry-dependent-properties-of-the-ferromagnetic-weyl-semimetal-zrco2-x-sn
#4
Satya K Kushwaha, Karoline Stolze, Zhijun Wang, Max Hirschberger, Jingjing Lin, B Andrei Bernevig, N Phuan Ong, Robert J Cava
We report the growth of high quality bulk crystals, through crystallization from molten Sn flux, of the predicted ferromagnetic Weyl metal ZrCo2-x Sn with the L21 Heusler phase structure. The concentration of Co vacancies in the single crystals is found to be dependent on the initial concentration of Co in the flux. The saturation magnetization increases approximately linearly with decreasing Co deficiency and the ferromagnetic transition temperature changes significantly. p-type carrier conduction and an anomalous Hall effect are observed...
April 25, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28440787/phase-behaviour-of-two-dimensional-mnwox-and-fewox-ternary-oxide-layers-on-pd-100
#5
Nassar Doudin, David Kuhness, Matthias Blatnik, Falko Netzer, Svetlozar Surnev
The structure and properties of ternary oxide materials at the nanoscale are poorly explored both on experimental and theoretical levels. With this work we demonstrate the successful on-surface synthesis of two-dimensional (2D) ternary oxide, MnWOx and FeWOx, nanolayers on a Pd(100) surface and on the understanding of their new structure and phase behaviour with the help of state-of-art surface structure and spectroscopy techniques. We find that the 2D MnWOx and FeWOx phases, prepared under identical thermodynamic conditions, exhibit similar structural properties, reflecting the similarity of the bulk MnWO4 and FeWO4 phases with the wolframite structure...
April 25, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28440786/magnetic-and-transport-properties-of-layered-compound-ce-sub-2-sub-te-sub-5-sub
#6
Dong Chen, Shuai Zhang, Yang Huaixin, Jianqi Li, Gen-Fu Chen
Ce<sub>2</sub>Te<sub>5</sub> single crystals were successfully grown using RbCl/LiCl flux method. The structure of Ce<sub>2</sub>Te<sub>5</sub> can be viewed as a combination of CeTe<sub>2</sub> and CeTe<sub>3</sub>. The experimental results of magnetic susceptibility <i>χ</i>(<i>T</i>), isothermal magnetization <i>M</i>(<i>H</i>), electrical resistivity <i>ρ</i>(<i>T</i>), and heat capacity <i>C</i>(<i>T</i>) show two clear anomalies at 5...
April 25, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28437258/magnetic-resonance-study-of-exchange-biased-ni-nio-nanoparticles
#7
Ashish Chhaganlal Gandhi, Jauyn Grace Lin
Finite sized Ni/NiO nanoparticles (NPs) are prepared by oxidizing pure Ni-NPs in an ambient atmosphere with varying annealing time (t A). A synchrotron radiation x-ray diffraction technique was used to estimate the grain size, weight fraction and lattice parameters of Ni and NiO. The temperature (T) dependencies of effective g-factor and line-width of ferromagnetic resonance (FMR) spectra for a series of Ni/NiO NPs are determined. Three T-regions with different FMR behaviors T  >  200 K, 200  >  T  >  130 K and T  <  130 K are identified...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28437257/creation-of-quasi-dirac-points-in-the-floquet-band-structure-of-bilayer-graphene
#8
W M Cheung, K S Chan
We study the Floquet quasi-energy band structure of bilayer graphene when it is illuminated by two laser lights with frequencies [Formula: see text] and [Formula: see text] using Floquet theory. We focus on the dynamical gap formed by the conduction band with Floquet index  =  -1 and the valence band with Floquet index  =  +1 to understand how Dirac points can be formed. It is found that the dynamical gap does not have rotation symmetry in the momentum space, and quasi-Dirac points, where the conduction and valence bands almost touch, can be created when the dynamical gap closes along some directions with suitably chosen radiation parameters...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28437256/electron-inelastic-mean-free-path-at-energies-below-100-ev
#9
Hieu T Nguyen-Truong
Knowledge of electron inelastic mean free paths (IMFPs) is important for electron spectroscopy and microscopy studies. Here, we determine the IMFPs at energies below 100 eV for 10 elemental solids (V, Fe, Ni, Mo, Pd, Ag, Ta, W, Pt, and Au) within the dielectric formalism, using the energy-loss function calculated in the adiabatic local-density approximation of time-dependent density-functional theory. The resulting IMFPs at a few eV above the Fermi energy are comparable to those from ab initio calculations in the GW approximation of many-body theory...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28437255/capped-carbon-nanotubes-with-a-number-of-ground-state-magnetization-discontinuities-increasing-with-their-size
#10
N P Konstantinidis
The classical ground state magnetic response of fullerene molecules that resemble capped carbon nanotubes is calculated within the framework of the antiferromagnetic Heisenberg model. It is found that the magnetic response depends subtly on spatial symmetry and chirality. Clusters based on armchair carbon nanotubes which are capped with non-neighboring pentagons and have D 5d spatial symmetry have a number of magnetization discontinuities which increases with their size. This occurs even though the model completely lacks magnetic anisotropy, and even though the only source of frustration are the two groups of six pentagons located at the ends of the molecules, which become more strongly outnumbered as the clusters are filled in the middle with more unfrustrated hexagons with increasing size...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28437254/interaction-driven-distinctive-electronic-states-of-artificial-atoms-at-the-zno-interface
#11
Tapash Chakraborty, Aram Manaselyan, Manuk Barseghyan
We have investigated the electronic states of planar quantum dots at the ZnO interface containing a few interacting electrons in an externally applied magnetic field. The electron-electron interaction effects are expected to be much stronger in this case than in traditional semiconductor quantum systems, such as in GaAs or InAs quantum dots. In order to highlight that stronger Coulomb effects in the ZnO quantum dots, we have compared the energy spectra and the magnetization in this system to those of the InAs quantum dots...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28437253/charge-transfer-driven-emergent-phenomena-in-oxide-heterostructures
#12
Hanghui Chen, Andrew Millis
Complex oxides exhibit many intriguing phenomena, including metal-insulator transition, ferroelectricity/multiferroicity, colossal magnetoresistance and high transition temperature superconductivity. Advances in epitaxial thin film growth techniques enable us to combine different complex oxides with atomic precision and form an oxide heterostructure. Recent theoretical and experimental work has shown that charge transfer across oxide interfaces generally occurs and leads to a great diversity of emergent interfacial properties which are not exhibited by bulk constituents...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28437252/valley-filtering-in-graphene-due-to-substrate-induced-mass-potential
#13
D R da Costa, A Chaves, G A Farias, F M Peeters
The interaction of monolayer graphene with specific substrates may break its sublattice symmetry and results in unidirectional chiral states with opposite group velocities in the different Dirac cones (Zarenia et al 2012 Phys. Rev. B 86 085451). Taking advantage of this feature, we propose a valley filter based on a transversal mass kink for low energy electrons in graphene, which is obtained by assuming a defect region in the substrate that provides a change in the sign of the substrate-induced mass and thus creates a non-biased channel, perpendicular to the kink, for electron motion...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28436385/structural-and-magnetic-properties-of-spin-1-2-dimer-compound-cu-_2-ipa-_2-dmf-h-_2-o-with-a-large-spin-gap
#14
S Thamban, Arjun U, M Padmanabhan, Ramesh Chandra Nath
We present the synthesis and a detailed investigation of structural and magnetic properties of metal-organic compound Cu$_2$(IPA)$_2$(DMF)(H$_2$O) by means of x-ray diffraction, magnetization, and heat capacity measurements. Single crystals of the title compound were synthesized by judicious selection of organic ligand and employing a selective hydrothermal reaction route. It crystallizes in an orthorhombic structure with space group $Cmca$. The structural analysis revealed that two Cu$^{2+}$ ions are held together by the organic component (-O-C-O-) in a square paddle-wheel to form spin dimers which are aligned perpendicular to each other and are further coupled through organic ligands (isophthalic acid) forming two-dimensional layers...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28436384/dynamical-electrical-conductivity-of-graphene
#15
Luxmi Rani, Navinder Singh
For graphene (a Dirac material) it has been theoretically predicted and experimentally observed that DC resistivity is proportional to $ T^4$ when the temperature is much less than Bloch-Gr\"{u}neisen temperature ($\Theta_{BG}$) and T-linear in opposite case ($T\gg\Theta_{BG}$). Going beyond this case, we investigate the dynamical electrical conductivity in graphene using the powerful methods the memory function formalism. In the zero frequency regime, we obtain the above mentioned behavior which was previously obtained using the Bloch-Boltzmann kinetic equation...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28436383/influence-of-point-defects-and-impurities-on-the-dynamical-stability-of-delta-plutonium
#16
Boris Dorado, Jordan Bieder, Marc Torrent
We use first-principles calculations to provide direct evidence of the effect of aluminum, gallium, iron, and uranium on the dynamical stability of delta-plutonium. We first show that the delta phase is dynamically unstable at low temperature, as seen in experiments, and that this stability directly depends on the plutonium 5f orbital occupancies. Then, we demonstrate that both aluminum and gallium stabilize the delta phase, contrary to iron. As for uranium, which is created during self-irradiation and whose effect on plutonium has yet to be understood, we show that it leaves a few unstable vibrational modes and that higher concentrations lead to an almost complete stabilization...
April 24, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28430111/wavepacket-dynamics-and-the-multi-configurational-time-dependent-hartree-approach
#17
Uwe Manthe
Multi-configurational time-dependent Hartree (MCTDH) based approaches are efficient, accurate, and versatile methods for high-dimensional quantum dynamics simulations. Applications range from detailed investigations of polyatomic reaction processes in the gas phase to high-dimensional simulations studying the dynamics of condensed phase systems described by typical solid state physics model Hamiltonians. The present article presents an overview of the different areas of application and provides on a comprehensive review of the underlying theory...
April 21, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28430110/viscosity-of-a-sheared-correlated-near-critical-model-fluid-in-confinement
#18
Christian Rohwer, Andrea Gambassi, Matthias Kruger
Second-order phase transitions are characterized by a divergence of the spatial correlation length of the order parameter fluctuations. For confined systems, this is known to lead to remarkable equilibrium physical phenomena, including finite-size effects and critical Casimir forces. We explore here some non-equilibrium aspects of these effects in the stationary state resulting from the action of external forces: by analyzing a model of a correlated fluid under shear, spatially confined by two parallel plates, we study the resulting viscosity within the setting of (Gaussian) Landau-Ginzburg theory...
April 21, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28430107/superconductivity-and-magnetic-fluctuations-developing-in-the-vicinity-of-strong-first-order-magnetic-transition-in-cras
#19
Hisashi Kotegawa, Kei Matsushima, Shingo Nakahara, Hideki Tou, Jun Kanetoshi, Taihei Nishiwaki, Eiichi Matsuoka, Hitoshi Sugawara, Hisatomo Harima
We report single crystal preparation, resistivity, and nuclear quadrupole resonance (NQR) measurements for new pressure-induced superconductor CrAs. In the first part, we present the difference between crystals made by different thermal sequences and methods, and show the sample dependence of superconductivity in CrAs. In the latter part, we show NQR data focusing the microscopic electronic state at the phase boundary between the helimagnetic (HM) and the paramagnetic (PM) phases. They suggest strongly that a quantum critical point is absent on the pressure-temperature phase diagram of CrAs, because of the strong first-order character of the magnetic transition; however, the spin fluctuations are observed in the PM phase...
April 21, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28430106/atomic-motions-in-the-layered-copper-pseudochalcogenide-cuncn-indicative-of-a-quantum-spin-liquid-scenario
#20
Andrei L Tchougreeff, Ralf Stoffel, Andreas Houben, Philipp Jacobs, Richard Dronskowski, Matej Pregelj, Andrej Zorko, Denis Arcon, Oksana Zaharko
We explore the thermodynamic properties of the layered copper(II) carbodiimide CuNCN by heat-capacity measurements and investigate the corresponding thermal atomic motions by means of neutron powder diffraction as well as inelastic neutron scattering. The experiments are complemented by a combination of density-functional calculations, phonon analysis and analytic theory. The existence of a soft flexural mode-bending of the layers, characteristic for the material structure-is established in the phonon spectrum of CuNCN by giving characteristic temperature-dependent contributions to the heat capacity and atomic displacement parameters...
April 21, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
journal
journal
40367
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"