In-plane optical anisotropy of two-dimensional VOCl single crystal with weak interlayer interaction

Abstract

MOX (M = Fe, Cr, V; O = oxygen, X = F, Cl, Br, I), an emerging type of two-dimensional (2D) van der Waals materials, have been both theoretically and experimentally demonstrated to possess unique electronic and magnetic properties. However, the intrinsic in-plane anisotropic properties of 2D VOCl still lacks in-depth research, especially optical anisotropy. Herein, a systematic Raman spectroscopic study is performed on VOCl single-crystal with different incident laser polarization at various temperatures. The polarized-dependent Raman scattering spectra reveal that the A g mode of VOCl show a 2-lobed shape in parallel polarization configuration while a 4-lobed shape in vertical configuration. In addition, the temperature-dependent and thickness-dependent Raman scattering spectra confirm a relatively weak van der Waals interaction between each layers among VOCl single crystal. These findings might provide better understanding on the in-plane anisotropic phenomenon in VOCl layers, thus will accelate further application of 2D single crystals for nanoscale angle-dependent optoelectronics.

First-principles predictions of room-temperature ferromagnetism in orthorhombic MnX2 (X = O, S) monolayers

“…Mechanical exfoliation of bulk is a common method for preparing 2D monolayers, 52,53 while chemical exfoliation is somewhat less common. However, chemical exfoliation was used to delaminate the layered antiferromagnet VOCl 54,55 which has a structure similar to MnX 2 monolayers. The exfoliation energy calculated for MnO 2 is 53 meV per atom (Table S1, ESI †), which is somewhat larger than that for graphene (10-20 meV per atom), 56 but smaller than that for oxide perovskite monolayers (SrTiO 3 monolayer B119 meV per atom).…”

The first-principles study on the magnetic and electronic properties of Janus Cr-based MXene

“…In recent years, two-dimensional materials, such as MOX [13,14], TMDs [15,16], h-BN [17,18], MXenes [19,20] are widely studied. Among them, two-dimensional transition metal carbon/nitride (MXenes) materials are excellent candidates for device applications due to their excellent stability, electrical conductivity and capacitance [21][22][23][24].…”

Unveiling the in-plane anisotropic dielectric waveguide modes in α-MoO3 flakes

“…[4] This unique property allows for easy exfoliation for material preparation and endows vdW materials with exceptional physical and chemical performance, making them a prime platform for developing future integrated photonic devices. [5][6][7] Graphene, with its outstanding electronic, [8,9] optical [10,11] and mechanical properties, [12,13] has become one of the most well-known vdW materials. [14][15][16][17][18] However, its zero-bandgap structure limits its application in digital devices and high-performance photodetectors.…”