Projected surface energy bands, Shockley surface states and stability of ordered substitutional alloys with CsCl structure: The example of β'-CuZn

1981 ◽  
Vol 46 (6) ◽  
pp. 1301-1317 ◽  
Author(s):  
Mojmír Tomášek ◽  
Štěpán Pick
Keyword(s):  
Surface Energy ◽  
Chemical Bonding ◽  
Surface States ◽  
Qualitative Theory ◽  
Energy Bands ◽  
Cscl Structure ◽  
Substitutional Alloys

Qualitative theory of Shockley surface states is applied to β'-CuZn with the aim to analyse the character and location of its hybridizational gaps and to draw general conclusions on other ordered substitutional alloys with CsCl structure as well. The results are used to propose the role which hybridizational gaps and chemical bonding can play in order-disorder phenomena of such alloys. Some special questions of relevance to these phenomena are also qualitatively discussed.

Projected surface energy bands of bcc iron

1974 ◽  
Vol 10 (2) ◽  
pp. 376-381 ◽  
Author(s):  
Ed Caruthers ◽  
Leonard Kleinman
Keyword(s):  
Surface Energy ◽  
Energy Bands ◽  
Bcc Iron

Surface states on random substitutional alloys

1985 ◽  
Vol 164 (1) ◽  
pp. 19-42 ◽  
Author(s):  
L.T. Wille ◽  
P.J. Durham
Keyword(s):  
Surface States ◽  
Substitutional Alloys

scholarly journals Surface structure of Gd20Co80 alloy

2021 ◽  
Vol 24 (1) ◽  
pp. 56-63
Author(s):  
V.G. Kudin ◽  
◽  
S.G. Rozouvan ◽  
V.S. Staschuk ◽  
◽  
...  
Keyword(s):  
Optical Constants ◽  
Surface States ◽  
Scanning Tunneling ◽  
Quantum Mechanical ◽  
Energy Bands ◽  
Tunneling Microscopy ◽  
Spectral Ellipsometry ◽  
Configurational Interaction ◽  
Mechanical Methods ◽  
Significant Difference

Gd 20 Co 80 alloy was studied applying experimental methods of spectral ellipsometry, atomic force and scanning tunneling microscopy. The experimental results exhibit the eutectic two-phase structure of this alloy. Clusters of a phase with a lower content had a lesser concentration of free carriers, which resulted in smaller tunnel currents during the measurements. To analyze the experimental data, a theoretical approach was developed, which was based both on the quantum-mechanical methods of configurational interaction and on three-diagonal Toeplitz matrices formalism. This approach allowed us to describe in detail the energy bands formation process in solid clusters with a relatively small quantity of atoms, which as a consequence enabled to describe the Shockley surface states as well as the existence of a surface layer with partially formed energy bands. Spectral-ellipsometric measurements of Gd 20 Co 80 alloy thin films confirmed a significant difference between the measured optical constants for 20-nm thick films and larger films. Quantum-mechanical molecular calculus allowed to obtain optical constants for several supercells of Gd-Co chemical compounds and confirmed the acquired experimental and theoretical results.

scholarly journals Interplay of symmetry and topology in science

2014 ◽  
Vol 70 (a1) ◽  
pp. C1419-C1419
Author(s):  
Boris Zhilinskii
Keyword(s):  
Classical System ◽  
Quantum Systems ◽  
Qualitative Theory ◽  
Topological Invariant ◽  
Particle Systems ◽  
Qualitative Description ◽  
Energy Bands ◽  
And Topology ◽  
Finite Particle

Qualitative methods in natural science are based mainly on simultaneous use of symmetry and topology arguments. The idea of the present talk is to demonstrate how the corresponding mathematical tools (based on symmetry and topology arguments) initially applied to describe classification of different phases of matter and transitions between them are extended to construct qualitative theory of finite particle systems and more general dynamical systems. I start with reminding basic notions and tools associated with application of group action ideas to physics as initiated and developed by Louis Michel (1923-1999) [1,2]. Then geometric combinatorial and topological ideas are used to give qualitative description of singularities of dynamical integrable classical system and their quantum analogs. Quantum monodromy and its various generalizations as well as description of energy bands of isolated finite particle quantum systems in terms of topological invariant, Chern number [3], will be discussed on concrete molecular and atomic examples.

scholarly journals Land-atmosphere interactions in an high resolution atmospheric simulation coupled with a surface data assimilation scheme

2009 ◽  
Vol 9 (5) ◽  
pp. 1613-1624 ◽  
Author(s):  
L. Campo ◽  
F. Castelli ◽  
D. Entekhabi ◽  
F. Caparrini
Keyword(s):  
Energy Balance ◽  
Data Assimilation ◽  
Surface Energy ◽  
Energy Budget ◽  
Land Surface ◽  
Surface States ◽  
Atmospheric Model ◽  
Turbulent Fluxes ◽  
Data Assimilation Scheme ◽  
Assimilation Scheme

Abstract. A valid tool for the retrieving of the turbulent fluxes that characterize the surface energy budget is constituted by the remote sensing of land surface states. In this study sequences of satellite-derived observations (from SEVIRI sensors aboard the Meteosat Second Generation) of Land Surface Temperature have been used as input in a data assimilation scheme in order to retrieve parameters that describe energy balance at the ground surface in the Tuscany region, in central Italy, during summer 2005. A parsimonious 1-D multiscale variational assimilation procedure has been followed, that requires also near surface meteorological observations. A simplified model of the surface energy balance that includes such assimilation scheme has been coupled with the limited area atmospheric model RAMS, in order to improve in the latter the accuracy of the energy budget at the surface. The coupling has been realized replacing the assimilation scheme products, in terms of surface turbulent fluxes and temperature and humidity states during the meteorological simulation. Comparisons between meteorological model results with and without coupling with the assimilation scheme are discussed, both in terms of reconstruction of surface variables and of vertical characterization of the lower atmosphere. In particular, the effects of the coupling on the moisture feedback between surface and atmosphere are considered and estimates of the precipitation recycling ratio are provided. The results of the coupling experiment showed improvements in the reconstruction of the surface states by the atmospheric model and considerable influence on the atmospheric dynamics.

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