Nuclear Quadrupole Resonance Spectrum ofLa2CuO4

I report the results of ab initio quantum chemistry calculations addressing the nuclear quadrupole resonance (NQR) spectra of hole-doped ${\mathrm{La}}_2{\mathrm{CuO}}_4$. The experimental spectra point to two Cu environments, with a main peak, corresponding to a predominantly $d^9$ Cu site, and a satellite at $\sim$3 MHz higher frequency. The cluster calculations exhibit broken-symmetry solutions in which an additional hole localizes on a single ${\mathrm{CuO}}_6$ unit, and predict a satellite in the NQR spectrum 2.7 MHz above the main peak. The satellite corresponds to Cu sites neighboring a localized hole. I conclude that some ( $\sim$25%) of the holes doped in to ${\mathrm{La}}_{2-x}{\mathrm{Sr}}_x{\mathrm{CuO}}_4$ are localized on the NQR time scale of $\sim$1 $\mu$sec.