Two-dimensional defect

The interaction of CO with the solid surface produces several physical and chemical effects on the vibrational properties of the adsorbed species. The adsorption of CO can be envisaged as a two-dimensional condensation, leading to lateral coupling between adsorbed molecules. The vibrational properties of adsorbed CO can thus be used to monitor the effects of other interface properties, such as surface defects, two-dimensional phase transitions [45] and co-adsorption. Finally, CO is formed as an intermediate or poison during the oxidation of several organic molecules at electrodes, thus constituting one of the subjects of interest in electrocatalysis. 

Park HG, Hwang JK, Huh J, Ryu HY, Kim SH, Kim JS, Lee YH (2002) Characteristics of modified single-defect two-dimensional photonic crystal lasers. IEEE J Quantum Electron 38(10) 1353-1365... 

Fig. 9. Schematic of a two-dimensional cross section of an AgBr emulsion grain showing the surface and formation of various point defects A, processes forming negative kink sites and interstitial silver ions B, positive kink site and C, process forming a silver ion vacancy at a lattice position and positive kink...

On the other hand, the formation of the high pressure phase is preceded by the passage of the first plastic wave. Its shock front is a surface on which point, linear and two-dimensional defects, which become crystallization centers at super-critical pressures, are produced in abundance. Apparently, the phase transitions in shock waves are always similar in type to martensite transitions. The rapid transition of one type of lattice into another is facilitated by nondilTusion martensite rearrangements they are based on the cooperative motion of many atoms to small distances. ... 

The last twenty years have seen a rapid development of surface physics. In particular, the properties of clean perfect surfaces (with two-dimensional periodicity) are henceforth well known and understood. In recent years, the focus has been put onto surfaces with defects (adatoms, steps, vacancies, impurities...) which can now be investigated experimentally due either to the progress of old techniques (field ion microscopy or He diffraction, for instance) or to the rapid development of new methods (STM, AFM, SEXAFS...). 

The disproportionation reaction destroys the layered structure and the two-dimensional pathways for lithium-ion transport. For >0.3, delithiated Li, AV02 has a defect rock salt structure without any well-defined pathways for lithium-ion diffusion. It is, therefore, not surprising that the kinetics of lithium-ion transport and overall electrochemical performance of Li, tV02 electrodes are significantly reduced by the transformation from a layered to a defect rock salt structure [76], This transformation is clearly evident from the... 

A considerable body of scientific work has been accomplished in the past to define and characterize point defects. One major reason is that sometimes, the energy of a point defect can be calculated. In others, the charge-compensation within the solid becomes apparent. In many cases, if one deliberately adds an Impurity to a compound to modify its physical properties, the charge-compensation, intrinsic to the defect formed, can be predicted. We are now ready to describe these defects in terms of their energy and to present equations describing their equilibria. One way to do this is to use a "Plane-Net". This is simply a two-dimensional representation which uses symbols to replace the spherical images that we used above to represent the atoms (ions) in the structure. 

---