Structural, electronic, vibration and elastic properties of the layered AgInPS semiconducting crystal - DFT approach.

Detailed first principles calculations of the structural, electronic and vibrational properties of the AgInPS crystal are reported. The energy band spectra of the mentioned material using DFT/GGA-D methodology with the PBE functional was calculated for the first time. Stability of the AgInPS crystals in contrast to Cu-containing representatives of M1M2PX materials family (M1, M2 - metal, X - chalcogen) has been explained in the framework of the second-order Jahn-Teller effect.

Tuning the electronic and vibrational properties of SnPSe and PbPS crystals and their metallization under high pressure.

External stimuli enabling either a continuous tuning or an abrupt switching of the basic properties of materials that are utilized in various industrial appliances could significantly extend their range of use. The key characteristics of semiconductors are basically linked to their electronic and optical properties. In this study, we experimentally demonstrated that two kindred wide-band-gap semiconductors, ferroelectric SnPSe and paraelectric PbPS, which are commonly used in optical technologies, have remarkably different and unusual responses in their electronic band structures to applied moderate pressures.

Antisite defects in layered multiferroic CuCr(0.9)In(0.1)P2S6.

The CuCr1-xInxP2S6 system represents a large family of metal chalcogenophosphates that are unique and promising candidates for 2D materials with functionalities such as ferroelectricity. In this work, we carried out detailed microstructural and chemical characterization of these compounds using aberration-corrected STEM, in order to understand the origin of these different ordering phenomena. Quantitative STEM-HAADF imaging and analysis identified the stacking order of an 8-layer thin flake, which leads to the identification of anti-site In(3+)(Cu(+)) doping.

CuInP₂S₆ Room Temperature Layered Ferroelectric.

We explore ferroelectric properties of cleaved 2-D flakes of copper indium thiophosphate, CuInP2S6 (CITP), and probe size effects along with limits of ferroelectric phase stability, by ambient and ultra high vacuum scanning probe microscopy. CITP belongs to the only material family known to display ferroelectric polarization in a van der Waals, layered crystal at room temperature and above. Our measurements directly reveal stable, ferroelectric polarization as evidenced by domain structures, switchable polarization, and hysteresis loops.