Abstract
We construct a new U(1)slave-spin representation for the single-band Hubbard model in the large-U limit.The mean-field theory in this representation is more amenable to describe both the spin-charge-separation physics of the Mott insulator at half-filling and the strange metal behavior at finite doping.By employing a dynamical Green's function theory for slave spins,we calculate the single-particle spectral function of electrons.The result is comparable to that in dynamical mean field theories.We then formulate a dynamical t/U expansion for the doped Hubbard model that reproduces the mean-field results at the lowest order of expansion.To the next order of expansion,it naturally yields an effective low-energy theory of a t-J model for spinons self-consistently coupled to an XXZ model for the slave spins.We show that the superexchange J is renormalized by doping,in agreement with the Gutzwiller approximation.Surprisingly,we find a new ferromagnetic channel of exchange interactions which survives in the infinite U limit,as a manifestation of the Nagaoka ferromagnetism.
基金项目
Startup Fund of Anhui University(S020118002/002)
Kavli Institute for Theoretical Sciences()
National Key Research and Development Program of China(2023YFA1406500)
国家自然科学基金(12334008)
国家自然科学基金(12174441)
维普
万方数据