Van der Waals(vdW)layered two-dimensional(2D)materials,which may have high carrier mobility,valley polarization,excellent mechanical properties and air stability,have been widely investigated before.We ex-plore the possibility of producing a spin-polarized two-dimensional electron gas(2DEG)in the heterojunction composed of insulators MoSi2N4 and VSi2N4 by using first-principles calculations.Due to the charge trans-fer effect,the 2DEG at the interface of the MoSi2N4/VSi2N4 heterojunction is found.Further,for different kinds of stacking of heterojunctions,lattice strain and electric fields can effectively tune the electronic struc-tures and lead to metal-to-semiconductor transition.Under compressive strain or electric field parallel to c axis,the 2DEG disappears and band gap opening occurs.On the contrary,interlayer electron transfer enforces the system to become metallic under the condition of tensile strain or electric field anti-parallel to c axis.These changes are mainly attributed to electronic redistribution and orbitals'reconstruction.In addition,we reveal that MoSi2N4/VSi2N4 lateral heterojunctions of armchair and zigzag edges exhibit different electronic proper-ties,such as a large band gap semiconductor and a metallic state.Our findings provide insights into electronic band engineering of MoSi2N4/VSi2N4 heterojunctions and pave the way for future spintronics applications.

Ruiling Gao;Chao Liu;Le Fang;Bixia Yao;Wei Wu;Qiling Xiao;Shunbo Hu;Yu Liu;Heng Gao;Shixun Cao;Guangsheng Song;Xiangjian Meng;Xiaoshuang Chen;Wei Ren

Physics Department,State Key Laboratory of Advanced Special Steel,Materials Genome Institute,Shanghai Key Laboratory of High Temperature Superconductors,International Center of Quantum and Molecular Structures,Shanghai University,Shanghai 200444,China;Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials(Ministry of Education),Anhui University of Technology,Maanshan 243002,China;State Key Laboratory of Surface Physics and Department of Physics,Fudan University,Shanghai 200433,China;State Key Laboratory of Infrared Physics,Shanghai Institute of Technical Physics,Chinese Academy of Sciences,Shanghai 200083,China

中国物理快报（英文版）

[1]Ruiling Gao;Chao Liu;Le Fang;Bixia Yao;Wei Wu;Qiling Xiao;Shunbo Hu;Yu Liu;Heng Gao;Shixun Cao;Guangsheng Song;Xiangjian Meng;Xiaoshuang Chen;Wei Ren-.Two-Dimensional Electron Gas in MoSi2N4/VSi2N4 Heterojunction by First Principles Calculation)[J].中国物理快报（英文版）,2022(12):57-64

VSi2N4

Two,Dimensional,Electron,Gas,MoSi2N4,Heterojunction,by,First,Principles,Calculation,Van,Waals,vdW,layered,two,dimensional,materials,which,may,have,high,carrier,mobility,valley,polarization,excellent,mechanical,properties,stability,been,widely,investigated,before,We,plore,possibility,producing,polarized,gas,2DEG,composed,insulators,using,first,principles,calculations,Due,charge,interface,found,Further,different,kinds,stacking,heterojunctions,lattice,strain,electric,fields,can,effectively,tune,electronic,tures,lead,semiconductor,transition,Under,compressive,parallel,axis,disappears,band,gap,opening,occurs,On,contrary,interlayer,transfer,enforces,system,become,metallic,under,condition,tensile,anti,These,changes,are,mainly,attributed,redistribution,orbitals,reconstruction,In,addition,we,reveal,that,lateral,armchair,zigzag,edges,exhibit,such,large,state,Our,findings,provide,insights,into,engineering,pave,way,future,spintronics,applications

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