In this work a periodic crystal with point defects is described in the framework of linear-response theory for broken-symmetry states using correlation functions and Zwanzig-Mori equations. The main results are microscopic expressions for the elastic constants and for the coarse-grained density, point-defect density, and displacement field, which are valid in real crystals, where vacancies and ...

Received 3 March 2021DOI:https://doi.org/10.1103/PhysRevB.103.159901©2021 American Physical SocietyPhysics Subject Headings (PhySH)TechniquesCrystal-field theoryCondensed Matter & Materials Physics

We have conducted two quantitative tests of predictions based on the Halperin-Lubensky-Ma (HLM) theory of fluctuation-induced first-order phase transitions. First, we explore the effect of an external magnetic field on the nematic-smectic- A transition in a liquid crystal. Second, we examine the dependence of the first-order discontinuity as a function of mixture concentration in pure 8CB and t...

The electronic structure of dodecahedral octacyanides of molybdenum IV and V is described in terms of SCCC molecular orbitals. Five MO's resemble d orbitals of the central atom. The splitting of appropriate levels is almost exactly the same as that following from the crystal field theory for GJG2 ~ 0.7. According to the theory stable Mo(CN)84" is dodecahedral and stable MO(CN)83is antiprismatic...