arXiv subjects

Kwangyl Park

Publications and source records attributed to Kwangyl Park.

2 recordsLinked to original sources

arXiv1999

Effects of nonmagnetic impurities on optical conductivity in strongly correlated systems

Effects of nonmagnetic impurities on optical conductivity in the systems of antiferromagnetically correlated electrons are examined based on the Lanczos exact diagonalization scheme. As a result of resonant scattering a low-frequency peak in the optical conductivity is predicted to occur in the presence of the nonmagnetic impurities, which is consistent with the observed normal-state optical conductivity of ${\rm YBa_2}({\rm Cu}_{1-x}{\rm Zn}_x)_3{\rm O}_{7-δ}$. In addition, a relatively high and broad peak is found to occur at a high frequency region as a consequence of the Heisenberg interaction between electrons, in agreement with observation in the peak position.

cond-mat.str-el↗

arXiv1999

Functional Schrödinger Representations of Holstein-Primakoff Boson and Slave-Boson Theories for Heisenberg Antiferromagnets

We present functional Schrödinger representations of Holstein-Primakoff boson and slave-boson theories for the Heisenberg Hamiltonian and the $t-J$ Hamiltonian respectively. Based on these representations we obtain the dispersion relations of magnons for two dimensional antiferromagnets. By applying the functional Schrödinger representation of the Holstein-Primakoff boson theory to the Heisenberg Hamiltonian, the exchange energy is correctly predicted and the self-energy of quasi-hole is obtained. From the use of the functional Schrödinger representation of the $t-J$ Hamiltonian it is shown that at half-filling the dispersion relation obtained from the slave-boson theory leads to that obtained from the Holstein-Primakoff boson approach.

cond-mat.str-el↗