Magnetic Couplings, Optical Spectra, and Spin-Orbit Exciton in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>5</mml:mn><mml:mi>d</mml:mi></mml:math>Electron Mott Insulator<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>Sr</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>IrO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>
Magnetic Couplings, Optical Spectra, and Spin-Orbit Exciton in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mn>5</mml:mn><mml:mi>d</mml:mi></mml:math>Electron Mott Insulator<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>Sr</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>IrO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>
Based on the microscopic model including strong spin-orbit coupling, on-site Coulomb and Hund's interactions, as well as crystal field effects, we have investigated magnetic and optical properties of Sr2IrO4. Taking into account all possible intermediate state multiplets generated by virtual hoppings of electrons, we calculated the isotropic Heisenberg, pseudodipolar, and …