"Nonlinear optics from ab-initio by means of the dynamical Berry-phase"
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We present an ab-initio real-time based computational approach to nonlinear
optical properties in Condensed Matter systems. The equation of motions, and in
particular the coupling of the electrons with the external electric field, are
derived from the Berry phase formulation of the dynamical polarization. The
zero-field Hamiltonian includes crystal local field effects, the renormalization
of the independent particle energy levels by correlation and excitonic effects
within the screened Hartree- Fock self-energy operator. The approach is
validated by calculating the second-harmonic generation of SiC and AlAs bulk
semiconductors: an excellent agreement is obtained with existing ab-initio
calculations from response theory in frequency domain. We finally show
applications to the second-harmonic generation of CdTe, MoS2, h-BN and the
third-harmonic generation of Si.
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References:
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Real-time approach to the optical properties of solids and nanostructures:
Time-dependent Bethe-Salpeter equation, Phys. Rev. B 84, 245110 (2011).
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Nonlinear optics from ab-initio by means of the dynamical Berry-phase,
C. Attaccalite and M. Gruning, Phys. Rev. B in press.