Enhanced out-of-plane piezoelectricity and carrier mobility in Janus γ -Sn2XY (X /Y= S, Se, Te) monolayers: A first-principles prediction

Abstract

In this Letter, we design Janus γ-[Formula: see text] ([Formula: see text] S, Se, Te) monolayers and predict their piezoelectricity and carrier mobility by using first-principles simulations. Janus γ-[Formula: see text] are found to be indirect semiconducting characteristics with a camel's back-like dispersion in the top valence band. We discovered that Janus γ-[Formula: see text] are piezoelectric with high out-of-plane piezoelectric coefficients. Our calculated results for the piezoelectricity demonstrate that the out-of-plane piezoelectric coefficient d31 of Janus γ-Sn2STe is calculated to be 1.02 pm/V, larger than that of other 2D structures. Moreover, our calculations for the transport features reveal that while the carrier mobility of γ-Sn2SSe is directionally isotropic, the electron mobility of both γ-Sn2STe and γ-Sn2SeTe exhibit high anisotropy along the two transport directions. The Janus γ-[Formula: see text] monolayers have high electron mobility, especially the electron mobility of γ-Sn2STe exceeds 105 cm2 V–1 s–1, which is potential for nanoelectronic applications.

Strong out-of-plane piezoelectricity and Rashba-type spin splitting in asymmetric structures: first-principles study for Janus γ-Sn2OX (X = S, Se, Te) monolayers

“…20 Due to the breaking of mirror symmetry, 2D Janus nanomaterials possess novel physical characteristics in comparison to their pristine symmetric structure, such as the out-of-plane piezoelectric effect. [21][22][23] Therefore, our aim in this paper is to design a series of Janus structures based on pristine g-SnX structures by oxygenation of chalcogen atoms in the top layer, namely Janus g-Sn 2 OX (X = S, Se, Te) monolayers.…”

Electronic, optical, and transport properties of single-layer ZrTeS4: a DFT study

“…8,9 The combination of transition metals and a wide range of chalcogenides enriches the advantages of these materials' properties, making them promising for many optoelectronic applications. [10][11][12][13][14][15] The TMDs with asymmetric electronic properties are called 2D Janus materials, 16,17 and this anisotropy results in many effects including Rashba spin splitting, second harmonic generation, and polarization of piezoelectricity. 16,18 Another sub-branch of TMDs are MXenes, whose constituent chalcogens are carbon or nitrogen.…”

First-principles examination of two-dimensional Janus quintuple-layer atomic structures XCrSiN2 (X = S, Se, and Te)

“…Two-dimensional (2D) materials have attracted interest in not only theoretical but also experimental studies due to their unique physicochemical characteristics. The distinct properties compared to the corresponding bulk phases make 2D materials become potential candidates for tremendous applications such as energy conversion, spintronics, 1–4 piezoelectric materials, 5 photocatalysts, 6 or supercapacitors, 7 etc. Currently, there are considerable types of 2D materials studied widely, including graphene, 8,9 transition metal dichalcogenides, 10–12 post-transition metal monochalcogenides, 13–15 stanene, 16 or germanene.…”