Spin-carrying Spin Polarons in the T-j Model *

The report discusses the spinless-fermion (holon) representation of the t-J model and describes a new analytical representation in which fermion operators are directly related to the physical electron operators and have spin. A simple, leading-order, treatment of the magnetic dynamics allows to take into account the spin-liquid aspect of the ground state. The obtained effective model, in comparison to that for holons, has an additional bare dispersion due to the hole moving by using quantum spin fluctuations present in the undoped antiferromagnetic ground state. The single-hole Green’s function at half-filling is then found numerically using the self-consistent Born approximation. For all quantities studied good or excellent agreement with numerical data is observed in the entire parameter range, much improving on the holon results. Using the introduced formalism, the two-hole problem is also studied by solving numerically the Bethe-Salpeter equation with noncrossing diagrams. The applicability of the method for the more general many-body doped case and some other related issues are discussed.