Tuesday, July 25, 2023
MLIT Room 310
E.G. Nikonov, R.G. Nazmitdinov, P.I. Glukhovtsev

Manifestation of the hexatic phase in confined two-dimensional systems with circular symmetry

Speaker: E.G. Nikonov

Quasi-two-dimensional systems play an important role in the manufacture of various devices for the needs of nanoelectronics. Obviously, the functional efficiency of such systems depends on their structural properties, which could change during phase transitions under the influence of external conditions (for example, temperature). Until now, the main attention has been focused on the search for signals of phase transitions in continuous two-dimensional systems. One of the central issues in such systems is the analysis of the conditions for the nucleation of the hexatic phase, which is accompanied by the appearance of defects in the Wigner crystalline phase at a certain temperature. However, for modern nanosystems, there arises both a practical and fundamental question about the critical number of electrons at which the symmetry of the crystal lattice begins to break in the system under consideration and, consequently, the nucleation of defects starts. The dependences of the orientational order parameter and the correlation function, which characterize topological phase transitions, are studied as functions of the number of particles at zero temperature. The result of calculations allows us to establish the precursors of the phase transition "hexagonal lattice - hexatic phase" for N=92,136,187, considered as an example.