scholarly journals Electron-phonon drag enhancement of transport properties from a fully coupled ab initio Boltzmann formalism

2020 ◽  
Vol 102 (24) ◽  
Author(s):  
Nakib H. Protik ◽  
Boris Kozinsky
Keyword(s):  
Ab Initio ◽  
Transport Properties ◽  
Phonon Drag ◽  
Fully Coupled

Ab initio investigations of the charge transport properties of endohedral M @C 20 ( M = Na and K) metallofullerenes

2010 ◽  
Vol 19 (11) ◽  
pp. 113402 ◽  
Author(s):  
Yi-Peng An ◽  
Chuan-Lu Yang ◽  
Mei-Shan Wang ◽  
Xiao-Guang Ma ◽  
De-Hua Wang
Keyword(s):  
Charge Transport ◽  
Ab Initio ◽  
Transport Properties

Ab Initio Study of the Sub-threshold Electron Transport Properties of Ultra-scaled Amorphous Phase Change Material Germanium Telluride

2014 ◽  
Vol 1697 ◽  
Author(s):  
Jie Liu ◽  
Xu Xu ◽  
M. P. Anantram
Keyword(s):  
Electron Transport ◽  
Ab Initio ◽  
Transport Properties ◽  
Defect States ◽  
Germanium Telluride ◽  
Voltage Curve ◽  
Current Voltage ◽  
Current Voltage Curve ◽  
Electron Transport Properties ◽  
Change Material

ABSTRACTThe sub-threshold electron transport properties of amorphous (a-) germanium telluride (GeTe) phase change material (PCM) ultra-thin films are investigated by using ab initio molecular dynamics, density function theory, and Green’s function simulations. The simulation results reproduce the trends in measured electron transport properties, e.g. current-voltage curve, intra-bandgap donor-like and acceptor-like defect states, and p-type conductivity. The underlying physical mechanism of electron transport in ultra-scaled a-PCM is unraveled. We find that, though the current-voltage curve of the ultra-scaled a-PCM resembles that of the bulk a-PCM, their physical origins are different. Unlike the electron transport in bulk a-PCM, which is governed by the Poole-Frenkel effect, the electron transport in ultra-scaled a-PCM is largely dominated by tunneling transport via intra-bandgap donor-like and acceptor-like defect states.

The transport properties of the cubic alkaline earths Ca, Sr, and Ba

1978 ◽  
Vol 56 (1) ◽  
pp. 161-174 ◽  
Author(s):  
J. G. Cook ◽  
M. J. Laubitz
Keyword(s):  
Large Deviations ◽  
Transport Properties ◽  
Thermoelectric Power ◽  
Phonon Scattering ◽  
Thermal Resistivity ◽  
Elastic Electron ◽  
Phonon Drag ◽  
Alkaline Earths ◽  
Conductivity Function ◽  
Electron Phonon Scattering

The electrical resistivity (ρ), thermoelectric power(S), and thermal conductivity (κ) of two Sr samples and two Ba samples have been determined from 30 to 300 K. Large deviations from Matthiessen's rule (DMR) were observed. The estimated transport properties for ideally pure Sr and Ba indicate that these elements, like Ca, show large deviations from the Bloch–Gruneisen form for ρ(T) at all temperatures, large and positive diffusion thermopowers with a negative phonon-drag contribution, and large deviations from the Wiedemann–Franz relationship (DWFR). In these respects, they are much more like the transition metals than the monovalent metals.In the second, analytical, portion of the paper we study the DWFR in some detail. First, the effect of lattice conduction is estimated, and found to be large. Then, a function X(E) of the electron energy, closely related to the conventional conductivity function σ(E), is estimated from the ρ and S data now available for Ca, Sr, and Ba above 300 K, and used to compute S and the Lorenz function for elastic electron–phonon scattering below 300 K. Comparison with the experimental data indicates that the energy dependence of the electron parameters is responsible for the electronic DWFR, and effects the diffusion thermoelectric power. Such 'band effects' may also be seen in the thermal resistivity due to inelastic scattering in at least Sr. Regrettably, we are not able to explain the observed DMR.

Thermodynamic and transport properties of meteor melt constituents from ab initio simulations: MgSiO 3, SiO 2, and MgO

2019 ◽  
Vol 125 (23) ◽  
pp. 235102 ◽  
Author(s):  
Justin B. Haskins ◽  
Eric C. Stern ◽  
Charles W. Bauschlicher ◽  
John W. Lawson
Keyword(s):  
Ab Initio ◽  
Transport Properties ◽  
Ab Initio Simulations ◽  
Thermodynamic And Transport Properties

Which states contribute to the tunneling current for large barrier thicknesses?

2006 ◽  
Vol 941 ◽  
Author(s):  
Christian Heiliger ◽  
Peter Zahn ◽  
Ingrid Mertig
Keyword(s):  
Ab Initio ◽  
Transport Properties ◽  
Tunnel Junctions ◽  
Tunneling Current ◽  
Interface Structure ◽  
Magnetic Configuration ◽  
Barrier Thickness

ABSTRACTThe transport properties of planar Fe/MgO/Fe tunnel junctions are investigated theoretically by means of ab initio calculations. In particular, the k||-resolved conductance in dependence on the barrier thickness, the interface structure, and the magnetic configuration is studied. The results show that the number of states in the k||-space contributing significantly to the overall current is decreasing with increasing barrier thickness as expected. In contrast to simple parabolic band models the contribution of states in the vicinity of k||=0, however, is only involved for a few considered configurations of the system Fe/MgO/Fe.

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