Advancing excited-state properties of two-dimensional materials using a dielectric-dependent hybrid functional
Arghya Ghosh, Subrata Jana, Manoar Hossain, Dimple Rani, Szymon Śmiga, Prasanjit Samal
Abstract
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.