We consider driving multiorbital Mott insulators using laser radiation. We derive general expressions for periodically driven spin-orbital models using time-dependent perturbation theory in the strong interaction limit. We show that the effective exchange interactions of the Floquet spin-orbital Hamiltonian are highly tunable via variations of the frequency, amplitude, and polarization of the laser. We also take the effect of a finite bandwidth of excitations into account and study possible heating effects. We further apply our formalism to orthorhombic titanates YTiO_{3} and LaTiO_{3} based on first-principles calculations, and we find that the spin exchange interactions in these compounds can be engineered to a large extent by tuning the frequency and electric-field amplitude of the laser.We consider driving multiorbital Mott insulators using laser radiation. We derive general expressions for periodically driven spin-orbital models using time-dependent perturbation theory in the strong interaction limit. We show that the effective exchange interactions of the Floquet spin-orbital Hamiltonian are highly tunable via variations of the frequency, amplitude, and polarization of the laser. We also take the effect of a finite bandwidth of excitations into account and study possible heating effects. We further apply our formalism to orthorhombic titanates YTiO_{3} and LaTiO_{3} based on first-principles calculations, and we find that the spin exchange interactions in these compounds can be engineered to a large extent by tuning the frequency and electric-field amplitude of the laser.

arXiv:1801.00401Physical Review LettersSep 4, 201845 citations

Strongly spin-orbit coupled Mott insulators

H. Takagi

Bulletin of the American Physical SocietyMar 6, 20140 citations

Mott Insulators : Physics and applications

Sindhunil Barman Roy

Jul 17, 20191 citation

Orbital Floquet engineering of exchange interactions in magnetic materials

Swati Chaudhary, David Hsieh, Gil Refael

We present a scheme to control the spin-exchange interactions by manipulating the orbital degrees of freedom using a periodic drive. We discuss two different protocols for orbital Floquet engineering. In one case, a periodic drive modifies the properties of the ligand orbitals which mediate magnetic interactions between transition-metal ions. In the other case, we consider drive-induced mixing of $d$ orbitals on each magnetic ion. We first find that an AC Stark shift of orbitals induces a change comparable to that induced from photoinduced hopping schemes, but expands the applicable frequency ranges. Next, we find that radiatively induced coherent vibrations provide a realistic path for Floquet orbital engineering with short pulses of electric fields weaker than 0.5 V/\AA{} producing $5%--10%$ changes in the magnetic coupling of Mott insulators such as the rare-earth titanates.We present a scheme to control the spin-exchange interactions by manipulating the orbital degrees of freedom using a periodic drive. We discuss two different protocols for orbital Floquet engineering. In one case, a periodic drive modifies the properties of the ligand orbitals which mediate magnetic interactions between transition-metal ions. In the other case, we consider drive-induced mixing of $d$ orbitals on each magnetic ion. We first find that an AC Stark shift of orbitals induces a change comparable to that induced from photoinduced hopping schemes, but expands the applicable frequency ranges. Next, we find that radiatively induced coherent vibrations provide a realistic path for Floquet orbital engineering with short pulses of electric fields weaker than 0.5 V/\AA{} producing $5%--10%$ changes in the magnetic coupling of Mott insulators such as the rare-earth titanates.

arXiv:1905.03921Physical review. B./Physical review. BDec 9, 201934 citations

Floquet spin and spin-orbital Hamiltonians and doublon-holon generations in periodically driven Mott insulators

Kasra Hejazi, Jianpeng Liu, Leon Balents

Intense light can alter the electronic properties of materials through its oscillating electric field. The effects on magnetic excitations in insulators, however, are indirect, since these are neutral and do not see the electric field directly. This study reports on how exchange interactions in single- and multiorbital Mott insulators are modified by electromagnetic radiation, whose frequency is assumed to be on the order of the Mott-Hubbard gap. The latter condition results in a nonvanishing creation rate of doubly occupied sites (doublons), which necessitates taking into account the finite bandwidth of the doublon excitations, a feature which goes beyond the na\"{\i}ve leading order strong correlation expansion. This ultimately leads to a complex-valued exchange parameter, where the real part represents the ``Floquet'' spin-exchange interaction, while the imaginary part reflects the creation rate of doublons.Intense light can alter the electronic properties of materials through its oscillating electric field. The effects on magnetic excitations in insulators, however, are indirect, since these are neutral and do not see the electric field directly. This study reports on how exchange interactions in single- and multiorbital Mott insulators are modified by electromagnetic radiation, whose frequency is assumed to be on the order of the Mott-Hubbard gap. The latter condition results in a nonvanishing creation rate of doubly occupied sites (doublons), which necessitates taking into account the finite bandwidth of the doublon excitations, a feature which goes beyond the na\"{\i}ve leading order strong correlation expansion. This ultimately leads to a complex-valued exchange parameter, where the real part represents the ``Floquet'' spin-exchange interaction, while the imaginary part reflects the creation rate of doublons.

arXiv:1809.09800Physical review. B./Physical review. BMay 9, 201926 citations

d

orbitals on each magnetic ion. We first find that an AC Stark shift of orbitals induces a change comparable to that induced from photoinduced hopping schemes, but expands the applicable frequency ranges. Next, we find that radiatively induced coherent vibrations provide a realistic path for Floquet orbital engineering with short pulses of electric fields weaker than 0.5 V/\AA{} producing

5%--10%

changes in the magnetic coupling of Mott insulators such as the rare-earth titanates.