Microscopic background in metal-insulator criterion for doped Mott-Hubbard materials

9^th World Congress on Materials Science and Engineering

June 12-14, 2017 Rome, Italy

Vladimir A Gavrichkov

Federal Research Center KSC, Siberian Branch of the RAS, Russia

Scientific Tracks Abstracts: J Material Sci Eng

Abstract :

Statement of the Problem: The purpose of this study is to construct a metalâ�?�?insulator criterion based on Wilson's ideas concerning a system of itinerant electrons in the analytical form for the doped Mottâ�?�?Hubbard materials and also to associate a microscopic background of criterion with real properties of these materials. Methodology & Theoretical Orientation: For our purposes, it is convenient to start with Lehmann's representation for the Green's function fg, f g G�?»�?» c c Ï�? �?»Ï�? �?»Ï�? = + of the intra-cell Hamiltonian with respect to the family of single-particle operators ( ) f c �?»Ï�? + and their matrix elements in the basis of ( , ) h S i N M eigenstates of 0 �?�?H (S and M are the spin and spin projection of the many-electron cell eigenstate), where index i runs over, �?¼, Ï�? and �?® and states in the different sectors of configuration space in Figure from the work. Findings: By following this approach, one obtains a simple metalâ�?�? insulator criterion, which is characterized by the condition: the number of first removal electron (frs) states 0 frs N = (-insulator) or 0 frs N > (-metal) irrespective of the doped hole concentration x. Conclusion & Significance: We suggest a non-adiabatic origin of the forbidden frs states and Hamâ�?�?s effect for their matrix elements as the probable reasons for insulator state of the doped materials with translational symmetry.

Biography :

Vladimir A Gavrichkov has experience in the study of the electronic structure of strongly correlated materials: iron borates with spin S=5/2, manganites (S=2) and cuprates (S=1/2).

Email: gav@iph.krasn.ru