Two-dimensional (2D) ferromagnetic semiconductors have attracted growing interest due to their potential applications in next-generation spintronic devices. Among them, the CrOCl monolayer stands out as a promising candidate, featuring intrinsic ferromagnetism, favorable air stability, and a moderate band gap. Despite its potential, the spin-dependent electronic and optical properties of CrOCl remain largely unexplored, presenting opportunities for advancing nanoscale spintronic technologies. In this work, we investigate how different magnetic configurations—ferromagnetic (FM) and antiferromagnetic (AFM)—influence the electronic band structure of 2D CrOCl. Our study employs density functional theory (DFT) with a range of effective Hubbard U parameters (from 0 to 5 eV, in increments of 1 eV) to account for electron correlation effects. Firstly, we investigate the geometric structure and the dynamic stability by plotting the phonon dispersion curves of the CrOCl monolayer and check the dynamic stability employing molecular dynamics ab initio. Secondly, we clearly remark that the intensity of the spin-up and spin-down DOS are sensitive to U in the two magnetic orders FM and AFM. We confirm this sensitivity by calculating the electronic band structures of CrOCl. In FM with different U cases, the spin-up and spin-down DOSs are asymmetric, which affirms that CrOCl is a ferromagnetic material. Here, we find that the spin-up band gap <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10948_2025_7021_Article_IEq1.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="37" /> </InlineMediaObject> <EquationSource Format="TEX">$E_{g, up}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>E</mi> <mrow> <mi>g</mi> <mo>,</mo> <mi>u</mi> <mi>p</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> and spin-down band energy <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10948_2025_7021_Article_IEq2.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="52" /> </InlineMediaObject> <EquationSource Format="TEX">$E_{g, down}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>E</mi> <mrow> <mi>g</mi> <mo>,</mo> <mi>d</mi> <mi>o</mi> <mi>w</mi> <mi>n</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> are not equivalent and are more sensitive to U. In contrast, in the case of AFM with different U, the spin-up and spin-down DOs are symmetric, and therefore, <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10948_2025_7021_Article_IEq1.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="37" /> </InlineMediaObject> <EquationSource Format="TEX">$E_{g, up}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>E</mi> <mrow> <mi>g</mi> <mo>,</mo> <mi>u</mi> <mi>p</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10948_2025_7021_Article_IEq2.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="52" /> </InlineMediaObject> <EquationSource Format="TEX">$E_{g, down}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>E</mi> <mrow> <mi>g</mi> <mo>,</mo> <mi>d</mi> <mi>o</mi> <mi>w</mi> <mi>n</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> are similar, but these band gaps energies are still sensitive to U. We also investigate optical properties such as the absorption coefficient, conductivity, and refractive index of the CrOCl two-dimensional sheet. In the <InlineEquation ID="IEq5"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10948_2025_7021_Article_IEq5.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="36" /> </InlineMediaObject> <EquationSource Format="TEX">$\alpha (\omega )$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>α</mi> <mo stretchy="false">(</mo> <mi>ω</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> spectrum, we see several peaks in the 0.0–25 eV range, which means strong absorption in this range. After that, the CrOCl monolayer becomes transparent when <InlineEquation ID="IEq6"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10948_2025_7021_Article_IEq6.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="81" /> </InlineMediaObject> <EquationSource Format="TEX">$\hbar \omega \ge 25.00$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ħ</mi> <mi>ω</mi> <mo>≥</mo> <mn>25.00</mn> </mrow> </math></EquationSource> </InlineEquation> eV.

Investigation of the Impact of the Ferromagnetic and Antiferromagnetic Order on the Electronic and Optical Properties of 2D CrOCl Using DFT(PBE)+U and DFT(B3LYP)+U

期刊论文
发表日期：

2025年7月12日

查看全文

Mohamed Barhoumi

摘要

Two-dimensional (2D) ferromagnetic semiconductors have attracted growing interest due to their potential applications in next-generation spintronic devices. Among them, the CrOCl monolayer stands out as a promising candidate, featuring intrinsic ferromagnetism, favorable air stability, and a moderate band gap. Despite its potential, the spin-dependent electronic and optical properties of CrOCl remain largely unexplored, presenting opportunities for advancing nanoscale spintronic technologies. In this work, we investigate how different magnetic configurations—ferromagnetic (FM) and antiferromagnetic (AFM)—influence the electronic band structure of 2D CrOCl. Our study employs density functional theory (DFT) with a range of effective Hubbard U parameters (from 0 to 5 eV, in increments of 1 eV) to account for electron correlation effects. Firstly, we investigate the geometric structure and the dynamic stability by plotting the phonon dispersion curves of the CrOCl monolayer and check the dynamic stability employing molecular dynamics ab initio. Secondly, we clearly remark that the intensity of the spin-up and spin-down DOS are sensitive to U in the two magnetic orders FM and AFM. We confirm this sensitivity by calculating the electronic band structures of CrOCl. In FM with different U cases, the spin-up and spin-down DOSs are asymmetric, which affirms that CrOCl is a ferromagnetic material. Here, we find that the spin-up band gap $E_{g, up}$ $E_{g, u p}$ and spin-down band energy $E_{g, down}$ $E_{g, d o w n}$ are not equivalent and are more sensitive to U. In contrast, in the case of AFM with different U, the spin-up and spin-down DOs are symmetric, and therefore, $E_{g, up}$ $E_{g, u p}$ and $E_{g, down}$ $E_{g, d o w n}$ are similar, but these band gaps energies are still sensitive to U. We also investigate optical properties such as the absorption coefficient, conductivity, and refractive index of the CrOCl two-dimensional sheet. In the $\alpha (\omega )$ $α (ω)$ spectrum, we see several peaks in the 0.0–25 eV range, which means strong absorption in this range. After that, the CrOCl monolayer becomes transparent when $\hbar \omega \ge 25.00$ $ħ ω \geq 25.00$ eV.