Boundary between bcc and hcp lattices in a 4He quantum crystal

Local oscillations in different models of the coherent bcc–hcp boundary in 4He and metals

“…The shape and spectrum of the local vibrations of the order parameter are found for both models of the PB. Basically, the role of interfaces for the existence of high dissipation and high diffusion is shown in nuclear magnetic resonance (NMR) experiments in solid mixtures of 3 He- 4 He [8,15,16]. We show that the local oscillation of the coherent phase boundaries may be responsible for these phenomena.…”

“…play an important role in determining the supersolid effects [8]. Special modeling conducted from the first principles by the Monte-Carlo method showed that in the perfect hcp 4 He crystal the supersolid effects cannot appear [9,10]. Possible kinds of disorder may be some defects such as grain boundaries [11], phase boundaries [12], a glass phase, or liquid inclusions.…”

“…1 Introduction Recent optical investigation of solid 4 He showed multiple nuclei formation of a new phase in the original single crystal with a bcc-hcp phase transition [1]. As a result, there are some secondary polycrystalline forms.…”

“…[4], we applied a theoretical description of the martensitic transition to describe the coherent bcc-hcp PB in solid 4 He. The order parameter or, in other words, the relative displacement of atomic planes, has been introduced.…”

“…In this paper, we investigate the small local vibrations in the coherent bcc-hcp boundaries in solid 4 He. Temporary Schrödinger equations for small local vibrations are derived in both models of the coherent PB.…”