Title: PHASE TRANSITIONS AND PHASE SEPARATION IN A PSEUDOSPIN-ELECTRON MODEL WITH DIRECT INTERACTION BETWEEN PSEUDOSPINS AND WITH TRANSVERSE FIELD
Author(s): Yu.I.Dublenych (Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Str., 79011 Lviv, Ukraine)

The pseudospin-electron model with a direct interaction between pseudospins and with transverse field is considered. In the absence of electron transfer, the equilibrium states of the model are studied in the mean field approximation. In the $\mu={}$const regime, two types of the first order phase transitions (with jumps of the mean values of pseudospins and average electron concentration) are revealed. At $T\to 0$, phase transitions of the first type disappear, on increasing the transverse field, while those of the second type persist at any large value of the field. The phase transitions of the second type are caused by simultaneous effect of pseudospin-electron interaction and transverse field. It is also shown that in the $n={}$const regime at zero temperature, the phase separation occurs at all values of a longitudinal field $h$.

Comments: Figs. 6, Refs. 8, Tabs. 0.