Path-integral theory for photoemission spectra of intermediately correlated systems Original Research Article

By using the quantum Monte-Carlo method, we calculated the Lehmann spectra of momentum-specified one-body Greenʹs functions as well as the total density of states (DOS), for one-dimensional half-filled Hubbard systems with various correlation strengths and temperatures. In the region of the intermediate correlation strength and temperature, we found that the DOS has new characteristic peaks near the Fermi level, in addition to the well-known upper and lower Hubbard-band peaks. We show these new peaks near the Fermi level are quasi-coherent, while the upper and lower Hubbard-band peaks are strongly incoherent. This multi-peaked structure in the intermediate region is also found to be insensitive to the dimensionality. Our results qualitatively agree with the recent experiment on CaVO3 and SrVO3.