Advancing excited-state properties of two-dimensional materials using a dielectric-dependent hybrid functional

Predicting accurate band gaps and optical properties of lower-dimensional materials, including two-dimensional van der Waals (vdW) materials and their heterostructures, remains a challenge within density functional theory (DFT) due to their unique screening compared to their bulk counterparts. Additionally, accurate treatment of the dielectric response is crucial for developing and applying screened-exchange dielectric-dependent range-separated hybrid functionals (SE-DD-RSH) for vdW materials. In this work, we introduce a SE-DD-RSH functional to the 2D vdW materials like <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:msub><a:mi>MoS</a:mi><a:mn>2</a:mn></a:msub></a:math>, <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:msub><b:mi>WS</b:mi><b:mn>2</b:mn></b:msub></b:math>, <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mrow><c:mi>h</c:mi><c:mi>BN</c:mi></c:mrow></c:math>, black phosphorus (BP), and <d:math xmlns:d="http://www.w3.org/1998/Math/MathML"><d:mi>β</d:mi><d:mtext>−</d:mtext><d:mi>InSe</d:mi></d:math>. By accounting for in-plane and out-of-plane dielectric responses, our method achieves accuracy comparable to advanced many-body techniques like <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mrow><e:msub><e:mi>G</e:mi><e:mn>0</e:mn></e:msub><e:msub><e:mi>W</e:mi><e:mn>0</e:mn></e:msub></e:mrow></e:math> and BSE@<f:math xmlns:f="http://www.w3.org/1998/Math/MathML"><f:mrow><f:msub><f:mi>G</f:mi><f:mn>0</f:mn></f:msub><f:msub><f:mi>W</f:mi><f:mn>0</f:mn></f:msub></f:mrow></f:math> at a lower computational cost. We demonstrate improved band gap predictions and optical absorption spectra for both bulk and layered structures, including some heterostructures like <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:msub><g:mi>MoS</g:mi><g:mn>2</g:mn></g:msub><g:mo>/</g:mo><g:msub><g:mi>WS</g:mi><g:mn>2</g:mn></g:msub></g:math>. This approach offers a practical and precise tool for exploring electronic and optical phenomena in 2D materials, paving the way for efficient computational studies of layered systems.