2 research outputs found
Crystal Structure and Chemical Bonding of Layered α‑In<sub>2</sub>Se<sub>3</sub>
Layered α-In2Se3 has found
widespread
applications in the electronic, optoelectronic, and thermoelectric
fields. However, the crystal structure of α-In2Se3, which plays a fundamental role in understanding its diverse
physical properties, remains poorly explored. In this study, we present
a comprehensive analysis of the temperature-dependent evolution of
lattice constants, fractional coordinates, and atomic displacement
parameters of α(3R)-In2Se3 using high-resolution
synchrotron powder X-ray diffraction. The temperature range of investigation
spans from 114.2 to 472.2 K. From temperature-dependent cell parameters,
the linear thermal expansion coefficients along the a-axis and c-axis at room temperature are determined
as 0.71 × 10–5 K–1 and 1.83
× 10–5 K–1, respectively,
giving rise to a marked anisotropy owing to the weak interlayer interactions
along the c-axis. Through modeling of isotropic atomic
displacement parameters, the Debye temperature is evaluated to be
173 K, showing good agreement with the result by fitting the low-temperature
heat capacity data. Furthermore, we conduct chemical bonding analysis
within the quantum theory of atoms in molecules and reveal that α(3R)-In2Se3 exhibits polar covalent intralayer bonds with
weak van der Waals interlayer interaction