scholarly journals Periodically driven adiabatic bipolarons

2016 ◽  
Vol 30 (18) ◽  
pp. 1650105 ◽  
Author(s):  
Pavel Kornilovitch

Small lattice bipolarons driven by external harmonic fields are considered in the adiabatic approximation. Resonant excitation of ions modulates the trapping potential and promotes hole transfer between neighboring atomic layers. It leads to a dramatic decrease of the apparent bipolaron mass compared to the undriven case. This effect offers an explanation for dynamic stabilization of superconductivity at high temperatures recently observed in layered cuprates.

2016 ◽  
Vol 7 (17) ◽  
pp. 3353-3358 ◽  
Author(s):  
Diana Gisell Figueroa del Valle ◽  
Luca Moretti ◽  
Isis Maqueira-Albo ◽  
Eduardo Aluicio-Sarduy ◽  
Ilka Kriegel ◽  
...  

Author(s):  
Z. L. Wang ◽  
J. Bentley

Studying the behavior of surfaces at high temperatures is of great importance for understanding the properties of ceramics and associated surface-gas reactions. Atomic processes occurring on bulk crystal surfaces at high temperatures can be recorded by reflection electron microscopy (REM) in a conventional transmission electron microscope (TEM) with relatively high resolution, because REM is especially sensitive to atomic-height steps.Improved REM image resolution with a FEG: Cleaved surfaces of a-alumina (012) exhibit atomic flatness with steps of height about 5 Å, determined by reference to a screw (or near screw) dislocation with a presumed Burgers vector of b = (1/3)<012> (see Fig. 1). Steps of heights less than about 0.8 Å can be clearly resolved only with a field emission gun (FEG) (Fig. 2). The small steps are formed by the surface oscillating between the closely packed O and Al stacking layers. The bands of dark contrast (Fig. 2b) are the result of beam radiation damage to surface areas initially terminated with O ions.


Author(s):  
N. David Theodore ◽  
Andre Vantomme ◽  
Peter Crazier

Contact is typically made to source/drain regions of metal-oxide-semiconductor field-effect transistors (MOSFETs) by use of TiSi2 or CoSi2 layers followed by AI(Cu) metal lines. A silicide layer is used to reduce contact resistance. TiSi2 or CoSi2 are chosen for the contact layer because these silicides have low resistivities (~12-15 μΩ-cm for TiSi2 in the C54 phase, and ~10-15 μΩ-cm for CoSi2). CoSi2 has other desirable properties, such as being thermally stable up to >1000°C for surface layers and >1100°C for buried layers, and having a small lattice mismatch with silicon, -1.2% at room temperature. During CoSi2 growth, Co is the diffusing species. Electrode shorts and voids which can arise if Si is the diffusing species are therefore avoided. However, problems can arise due to silicide-Si interface roughness (leading to nonuniformity in film resistance) and thermal instability of the resistance upon further high temperature annealing. These problems can be avoided if the CoSi2 can be grown epitaxially on silicon.


Author(s):  
S.R. Summerfelt ◽  
C.B. Carter

The wustite-spinel interface can be viewed as a model interface because the wustite and spinel can share a common f.c.c. oxygen sublattice such that only the cations distribution changes on crossing the interface. In this study, the interface has been formed by a solid state reaction involving either external or internal oxidation. In systems with very small lattice misfit, very large particles (>lμm) with coherent interfaces have been observed. Previously, the wustite-spinel interface had been observed to facet on {111} planes for MgFe2C4 and along {100} planes for MgAl2C4 and MgCr2O4, the spinel then grows preferentially in the <001> direction. Reasons for these experimental observations have been discussed by Henriksen and Kingery by considering the strain energy. The point-defect chemistry of such solid state reactions has been examined by Schmalzried. Although MgO has been the principal matrix material examined, others such as NiO have also been studied.


1990 ◽  
Vol 51 (8) ◽  
pp. 709-722 ◽  
Author(s):  
H.P. Breuer ◽  
K. Dietz ◽  
M. Holthaus

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