Magnetic Order Phase Of Hubbard Model On The Kagome Lattice

Quantum spin liquid(QSL)is one of the hotspots in the field of condensed matter.It is of great significance for understanding the mechanism of high temperature superconductivity.At present,quantum spin liquids are most likely to appear in honeycomb lattices,kagome lattices and square lattices.The Kagome lattice has strong geometrical frustration and quantum fluctuations,and is the most ideal material structure for the discovery of quantum spin liquids,and its basic properties are of great research significance.However,for the electronic ordered phase of the kagome lattice near the van Hoff filling,there is a dispute between the calculation results of pFRG and SMFRG,about whether the FM sequence is generated under the large Hubbard interaction U.In this paper,we use the RPA approximation and the mean field approximation to study the magnetic ordered phase of Kagome lattice near 1/6 hole doping.Our result shows that the Kagome lattice spin system only has a FM order when U<U0≈1.5t,and when U>U0,the system will appear AFM order as the temperature decreases.As U increases,the phase transition temperature of the system also gradually increases.In the introduction,we briefly introduce the quantum spin l iquid and derive the Hubbard model Hamiltonian.In the second chapter,we introduce the configuration of the kagome lattice,as well as the tight-binding energy band and density of states.In the third chapter,we first give the RPA corrected magnetic susceptibility calculation formula,and then show the ferromagnetic and antiferromagnetic instability curves of the Kagome lattice.In the fourth chapter,we first derive the mean field approximation Hamiltonian of the Kagome lattice and the iterative equations of order parameters.Then we show the energy band diagram and the magnetic phase diagram,and compare it with the results of DMFT.In the fifth chapter,we summarize the full text.