$\beta\Longleftrightarrow\beta'$ phase transition with temperature hysteresis in In$_2$Se$_3$ films

The temperature dependences of Raman scattering for In$_2$Se$_3$ films were measured during cooling to the liquid nitrogen temperature and subsequent heating to the room temperature. The Raman spectra show a reversible $\beta$-In$_2$Se$_3\Longleftrightarrow \beta'$-In$_2$Se$_3$ phase transition with hysteresis in the range of 140–180 K previously discovered by a change in the atomic structure of the surface and the sharp decrease in electrical resistance by a factor of $\sim$10$^4$ during the cooling. The ARPES measurements display changes in film's band structure corresponding to this phase transition.