Study On Performance Tuning Of One-Dimensional Janus MoSSe/WSSe Su-Perlattice Nanoribbons Based On First-Principle Method

Graphene-like materials,especially transition metal sulfides?TMDCs?,have caused extensive research due to their natural band gaps and excellent physical prop-erties.The hybrid system composed of transition metal sulfide materials provides more opportunities for electronic and optoelectronic properties.Among them,the su-perior properties of superlattice systems in terms of thermoelectric materials have at-tracted attention.With the development of current electronic technology,various components of the device should continue to shrink and maintain high performance characteristics to meet people's growing demand for material experience.So exploring one-dimensional nanoribbons has important technical significance.In recent experi-ments,a single-layered two-sided MoSSe?JMoSSe?with a symmetrically broken structure has been successfully synthesized,which has excellent properties such as intrinsic vertical piezoelectric effect and enhanced Rashba spin-orbit interaction.Considering that the properties of WSSe are similar to MoSSe in nature and the lattice constants are matched,in this work,we use a first-principles calculation method based on density functional theory to study the one-dimensional MoSSe/WSSe superlattice nanoribbons and the modulation effects of physical properties.The main research contents and results are as follows:?1?The zigzag JMoSSe/WSSe superlattice nanoribbons?Z-JSLNR?with differ-ent widths,as well as the distribution of S and Se atoms,composition ratios,and pe-riod lengths on the physical properties of the Z-JSLNR.The results show that as the width of the nanoribbons increases,Z-JSLNR has a transition from non-magnetic semiconducting to magnetic semi-metallic properties,tuning the distribution of S and Se atoms on both sides of the metal Mo and W atoms can be suppresses the phenom-enon of spontaneous bending of the structure,and does not change the band structure properties.The band gap of the superlattice decreases as the composition ratio be-tween the MoSSe material and the WSSe material increases,with a composition ratio of 4/2 and 5/1,the energy band spin splitting phenomenon also appears,resulting in magnetic moments of 2.0 and 4.0 ?B/cell,the band gap of the superlattice decreases as the period length of the two component materials increases,and the energy band gradually becomes to be flat and the locality of the charge is enhanced.?2?The armchair type JMoSSe/WSSe superlattice nanoribbons?A-JSLNR?with different widths,and the effects of S,Se atom distribution,composition ratio,and pe-riod length on the structure and physical properties of A-JSLNR were studied.The results show that as the width of the nanoribbon increases,the band gap of A-JSLNR undergoes oscillating changes.Regularly adjusting the distribution of S and Se atoms on both sides of the metal Mo and W atoms can suppress the phenomenon of sponta-neous bending of the structure,and it will not change the band structure properties,and the band gap of the superlattice varies slightly with the composition ratio between the MoSSe material and the WSSe material,and the band gap fluctuates around 1.1 eV;the band gap decreases with the increase of period length of the two constituent materials.And the energy band gradually becomes flat,and the locality of the charge increases.?3?The effects of strain and external electric field on the electronic and mag-netic properties of A_N-JSLNR with different widths are studied.In the strain range of-16%to 22%,the band gap of A_N-JSLNR increases first and then decreases,and the band gap can be linearly regulated in the range of 1 eV.Among them,the imaginary part and real part of the dielectric constant of A₆-JSLNR show anisotropy along the polarization directions of x,y,and z,and the red shift phenomenon appears with in-creasing strain.Under the external electric field,A_N-JSLNR with different widths still remains non-magnetic.With the electric field in the range of 0.4 V/A,the band gap decreases slightly.When the electric field increases again,the band gap decreases sharply to zero,there is a transition from semiconductor to metallic.In addition,by combining these two modulation methods,applying an electric field on the basis of applying different strains can improve performance regulation.We have studied the electronic structure properties of A_N-JSLNR through the regulation of strain and ex-ternal electric field,which provides a favorable theoretical guidance for the prepara-tion of related electronic devices in the future,and provides a feasible method for the performance control of nano-devices based on this new type of nano-scale materials.