Experimental and Theoretical Studies on α-In₂Se₃ at High Pressure

Abstract

α(R)-InSe has been experimentally and theoretically studied under compression at room temperature by means of X-ray diffraction and Raman scattering measurements as well as by ab initio total-energy and lattice-dynamics calculations. Our study has confirmed the α ( R3 m) → β' ( C2/ m) → β ( R3̅ m) sequence of pressure-induced phase transitions and has allowed us to understand the mechanism of the monoclinic C2/ m to rhombohedral R3̅ m phase transition. The monoclinic C2/ m phase enhances its symmetry gradually until a complete transformation to the rhombohedral R3̅ m structure is attained above 10-12 GPa. The second-order character of this transition is the reason for the discordance in previous measurements. The comparison of Raman measurements and lattice-dynamics calculations has allowed us to tentatively assign most of the Raman-active modes of the three phases. The comparison of experimental results and simulations has helped to distinguish between the different phases of InSe and resolve current controversies.

Superior Gas Sensing Properties of $β$-In$_2$Se$_3$: A First-Principles Investigation

“…Such property changes are useful in the sensing of NO molecules. This result corroborates those of NO molecule on α-In 2 Se 3 33 and InSe. 51 Such alterations in electronic properties for the NO 2 and NO absorbent play a significant role in gas sensing by charge transfer based sensors.…”

“…27,28 It is a polymorphic non-transition metal chalcogenide that crystallizes in five distinct polymorphs namely α, β, γ, δ and κ depending on growth temperature and pressure. [29][30][31][32][33][34] The α-and β-phases experience van der Waals interactions 29,35 making them suitable for several applications including phase-change memory, 36 e-skin applications, 37 optoelectronics, 26,38 and photodetection 39 to list a few. While both phases possess similar geometries, they exhibit significant difference in electronic properties.…”

Ferroelectric α‐In2Se3 Wrapped‐Gate β‐Ga2O3 Field‐Effect Transistors for Dynamic Threshold Voltage Control

“…[ 24–26 ] The other peaks observed at ≈89, 104, 180, and 196 cm −1 correspond to E 2 , A 1 1 , E 4 , and A 1 3 modes of α‐In 2 Se 3 , respectively. [ 27,28 ] Except for the Raman modes corresponding to α‐In 2 Se 3 and β‐Ga 2 O 3 , an additional peak near 143 cm −1 with a broad spectrum was observed from the area of α‐In 2 Se 3 /β‐Ga 2 O 3 heterojunction. The additional vibration mode can be related to a thin amorphous oxide IL formed at the interface between α‐In 2 Se 3 and β‐Ga 2 O 3 .…”

Negative linear compressibility and unusual dynamic behaviors of NaB3

“…Unexpectedly, the phase transition from the P 4/mbm to P bam phase is quite different from those second-order phase transitions [38][39][40][41], because it is accompanied by the emergence of anomalous lattice expansion along the crystallographic a-axis (belong to the proper ferroelastic transitions [5]) whereas normal lattice contractions along the b-and c-axes within pressure range of ∼16-26 GPa [Fig. 2(a)].…”