The External Field Control Of The Nearly Free Electronic State Of The Two-dimensional MXene Material

The theoretical and experimental exploration of two-dimensional materials'structure and properties really began since the monolayer graphene was successfully stripped by Novoselov and Gein in 2004.Also some materials whose structure are similar to graphene?such as BN,MoS₂?were prepared successfully later.Recently,a new kind of Two-dimensional material,Two-dimensional MXene materials was prepared.Two-dimensional MXene materials presents lots of promising usage in many fields?such as energy storage,catalysis,adsorption,hydrogen storage,sensors,new polymer reinforcement and etc.?which greatly aggravate people's understanding,and made large scientific works focus on its properties.Recently our research reflects that nearly-free-electron states exists in Two-dimensional MXene materials near the fermi level which were affected by image potential and some of metallic properties are characterized,but some of others are semiconductors.By research,we noticed that the structure terminated by different groups?such as OH,F,O?whose group is OH may get low work function and lower ground-state energy.In this paper our research subject concentrates on the nearly-free-electron-states'properties ofSc₂ C?OH?₂with and without the external Gate voltage.The contents will be mainly presented as follows:First,we take the approach of the theory of phono spectral caculate and analysis sixdifferent crystal structure of the material and found the three structure AA,AB,BB whose spectral of phono is above the axis of horizon coordinates,thus they are stable structure.Then,we take the image potential as the surface potential in the one-demenssional Schrodinger function and made the deduction of the wave function of the nearly-free-electron-states',and.then we caculate the the density of states distribution and the number of electron of spatial of the nearly-free-electron-states',noticed that the two nearly-free-electron-states 1⁺2,^-whose density of states'and spatial electron number‘s maxmum value are near the surface of the material which can be the ideal electronic transport channel.And then the theory of group was take to analysis the three crystal's?AA,AB,BB?symmetry,they belongs to different spatial groups?AA,BB:p3^-m1;AB:p3m1?,also there band structure are different?AB,BB:direct bandgap semiconductor;AA:indirect bandgap semiconductor?.The density of states is projected on each atom near the?point and we found the Sc and C whose density of states contributes more than other atoms to the whole density of states,thus we studied the partial orbit of Sc and C atom,which present that the d partial of Sc and the p partial of Ccontributed more than other partials to the valence band.Finally,the Non-Equilibrium Green's Function method is used to analysis the electronic transportation properties.and compared its'results to the simulation results while we made the gate voltage bigger and bigger.We noticed that the current become clear increasingly when the gate voltage become bigger,and the same trend appeared in the computer simulation results which reflects that the band gap become smaller and finally disappeared when the voltage become bigger and the material convert from semiconductor to conductor.