First-principles Calculation Of Two Dimensional Elemental Metals In A Single Atomic Layer

Since the discovery of graphene,two-dimensional(2D)materials have been extensively studied,and the family of 2D materials has been growing.Up to now,the 2D materials studied are mainly non-metallic elements,but the research on metal elements is less.Because the 2D metal with metal bonds is different from the 2D material with covalent bonds,we know that three-dimensional(3D)metals tend to be densely packed,so it is difficult to prepare and characterize 2D metals.However,2D metals with single atomic layer thickness,such as Stannene,Hafnium and Potassium,have also been prepared experimentally.In the periodic table of elements,most of the elements are metallic.So far,people have only studied the 2D structure of several metals or the 2D basic structure of common metals,but they have not studied the electronic structure and magnetic properties systematically.In the field of magnetism,when 3D bulk materials go to 2D planar materials,the magnetic properties of materials will change greatly.In this thesis,the density functional plane wave method is used to study the single atomic layer structure of 45 common metal elements in the periodic table of elements.The research contents are mainly divided into two parts.The first part mainly studies the basic properties of 45 metal elements,such as bond length,energy,etc.The second part mainly studies the magnetic properties of 2D metals.Firstly,for 45 metal elements studied,each element constructs three lattice types,namely triangular lattice,square lattice and hexagonal honeycomb lattice.By calculating the most stable structure of each lattice type,the lattice constants,bond energies and some mechanical properties of each element with these three structures are obtained,and compared with the corresponding 3D bulk.The changes in bond lengths and bond energies are analyzed when the material changes from 3D to 2D.Then,we studied the magnetism of single-layer 2D metals.By calculating,we found that besides Chromium,Manganese,Iron,Cobalt and Nickel in the 3D structure,at least one of the 13 elements exhibited ferromagnetism or antiferromagnetism in three lattice types.We studied the different magnetic configurations of the existing single atomic layer structure,found the magnetic ground states of each element,and we also studied the magnetic ground states of each element.The electronic structure of iron has been deeply analyzed.I hoped that our work will be of some guiding significance for future experimenters to study 2D metals.