Anomalous layer-dependent electronic and piezoelectric properties of 2D GaInS3 nanosheets

Abstract

Two-dimensional (2D) GaInS3 nanosheets are found to exhibit thermal and structural stabilities, good oxidation resistance, and tunable and layer-dependent electronic properties from first-principles calculations. Remarkably, the nanosheets with arbitrary thickness possess robust in-plane piezoelectricity without the odd-even effect commonly observed in other 2D piezoelectric materials, which is attributed to the retention of noncentrosymmetry resulting from their homogeneous and direct stacking patterns. The piezoelectric stress coefficient e113D of the nanosheets is about 0.23 C/m2, almost independent of the numbers of atomic layers of 2D GaInS3. The stability in piezoelectricity and the high carrier mobility of 2D GaInS3 nanosheets could endow them with promising application prospects in nanoelectronic and nanoelectromechanical devices.

High-refractive index and mechanically cleavable non-van der Waals InGaS3

“…In this article, we explore the optostructural properties of the hexagonal phase of InGaS3 expanding the list of non-van der Waals materials. We demonstrate that unlike orthorhombic InGaS3 predicted theoretically 20 , its hexagonal phase obeys a non-layered arrangement of crystal structure. Peculiarly, it can be cleaved down to atomically thin sheets due to the presence of few and delicate out-of-plane bonds within its unit cell.…”

“…Furthermore, our evaluations confirm the crystal structure of InGaS3 (see inset of Figure 1(a)) since dielectric response is a fingerprint of the material's electronic bandstructure (see Supplementary Information for details). We also evaluated optical constants for the orthorhombic phase of InGaS3 predicted theoretically in recent work 20 . Obtained constants are presented in Supplementary Figure S7.…”

“…Supplementary material contains extra characterization results of non-van der Waals InGaS3 sheets by a variety of techniques: energy-dispersive X-ray analysis, Raman spectroscopy, transmission electron diffraction patterns, AFM scans of inhomogeneous ultrathin sheets. It incorporates the summary data on X-ray diffraction patterns, and includes first-principle evaluation of optical constants along with CASTEP calculations of Raman-active modes for recently reported 20 orthorhombic phase of InGaS3.…”

Anomalous Anisotropy of the Piezoelectric Response in 2D Copper‐Based Ternary Chalcogenides CuMX2

“…Numerous efforts have been made in the past decade to design and develop novel 2D piezoelectric materials for the demand of practical devices. [ 14–28 ] It is worth noting that the calculated piezoelectric coefficient of the MoS 2 monolayer has been confirmed by subsequent experiment, [ 14,18 ] indicating that theoretical calculation is an effective approach in evaluating piezoelectricity and will play a significant and unique role in studying 2D materials. At the same time, some unique characteristics and mechanisms in 2D piezoelectric materials have been proposed successively, such as anisotropic and multidirectional piezoelectricity, [ 16,19,24 ] coexistence of out‐of‐plane and in‐plane piezoelectricity, [ 15,23 ] direct correlation between the piezoelectricity and atom polarizability, [ 15,19,26,28 ] and layer‐dependent piezoelectricity.…”

“…At the same time, some unique characteristics and mechanisms in 2D piezoelectric materials have been proposed successively, such as anisotropic and multidirectional piezoelectricity, [16,19,24] coexistence of out-of-plane and in-plane piezoelectricity, [15,23] direct correlation between the piezoelectricity and atom polarizability, [15,19,26,28] and layer-dependent piezoelectricity. [18,25] Although the piezoelectricity in 2D systems has some advantages, they are inadequate to support the replacement of traditional 3D piezoelectric crystals by 2D counterparts. Of course, to satisfy the device demands of microminiaturization and functionalization, further developments in searching novel 2D piezoelectric materials and illuminating their origin of piezoelectricity are still essential.…”