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Second Harmonic Generation From Surfaces Nicolas Tancogne-Dejean, Valérie Véniard

Second Harmonic Generation From Surfaces Nicolas Tancogne-Dejean, Valérie Véniard. Laboratoire des Solides Irradiés,Ecole Polytechnique, CNRS, CEA/DSM European Theoretical Spectroscopy Facility. Outline. Nonlinear optic and second harmonic generation Surfaces

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Second Harmonic Generation From Surfaces Nicolas Tancogne-Dejean, Valérie Véniard

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  1. Second Harmonic Generation From SurfacesNicolas Tancogne-Dejean, Valérie Véniard Laboratoire des Solides Irradiés,Ecole Polytechnique, CNRS, CEA/DSM EuropeanTheoreticalSpectroscopyFacility Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  2. Outline Nonlinear optic and second harmonic generation Surfaces How do we get the surface spectrum for SHG Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  3. Response to a perturbation Perturbation Response Polarisation Electric field LinearResponse NonlinearResponse • SumfrequencyGeneration • Absorption • Kerr effect • Refraction • Pockelseffect • Four-wavemixing • … • Birefringence • … Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  4. Second harmonic generation First nonlinear term Centrosymmetricmaterial : First nonlinear term : Non centrosymmetricmaterial : G. Frankel Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  5. Applications of second harmonic generation (SHG) Nanotubes characterization(PRB 77 125428) Biological tissues/neurons imaging (Biophys. J. 81 493; PNAS 103, 786) Nanoparticles imaging and microscopy ( C-L Hsieh PhD thesis, Caltech 2011 ) Thin films and surfaces characterization(PRB 89 075110) Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  6. Outline Nonlinear optic and second harmonic generation Surfaces How do we get the surface spectrum for SHG Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  7. Surfaces Different surfaces for the same material (e.g. Silicon) Si(111) 7x7 Si(001) 2x1 Asymmetric dimers Dangling bonds Si(001) 4x2 Surface = symmetry breaking Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  8. Model of surface – Super-cells Best representation of a surface Plane waves What we want Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  9. Model of surface – Super-cells Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  10. Outline Nonlinear optic and second harmonic generation Surfaces How do we get the surface spectrum for SHG Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  11. Second order response in Time-Dependent DFT Ground state (DFT) - Electronic structure : LDA functional - ABINIT code Second order response Independent Particles Approximation (IPA) Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  12. Extraction of one surface signal Direct Calculation Vacuum Front • Inversion symmetry Surf. C(z) Back Surf. Vacuum [1] L. Reining et al., Phys. Rev. B 50, 8411 (1994) It is possible to extract the signal from only one surface, using a new operator instead of p[1] Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  13. Second-order response z C(z) function ab initio calculation Extracted Signal C(z) Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  14. Extraction from two super-cells z z Signal from clean surface from two different super-cells Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  15. Extraction from two super-cells z z Independence of the two surfaces Signal from dihydride surface from two different super-cells Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  16. Extraction from two super-cells z z Independence of the two surfaces Calculation of the second orderresponsefromonly one surface Signal from dihydride surface from two different super-cells Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  17. Some results for Si(001)2x1 Clean Surface Monohydride Adaptedfrom J. I. Dadap, et al., Phys. Rev. B 56, 13367 (1997) Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  18. Some results for Si(001)2x1 Clean Surface Monohydride Adaptedfrom J. I. Dadap, et al., Phys. Rev. B 56, 13367 (1997) ab initiocalculations 40 Si atoms – 256 k-points Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  19. Conclusion Conclusion Perspective We have presented a scheme for extracting the response from one surface in a super-cell approach Beyond the Independent Particle Approximation - Local-field effects - Many body effects Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  20. Thank you for your attention Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  21. Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  22. Validation of the approach z Comparisonwith exact results for somespecific components of the tensor Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  23. Validation of the approach z Comparisonwith exact results for somespecific components of the tensor Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

  24. Some results for Si(001)2x1 Clean Surface Monohydride Adaptedfrom J. I. Dadap, et al., Phys. Rev. B 56, 13367 (1997) ab initiocalculations 40 Si atoms – 256 k-points Condensed Matter in Paris - CMD 25 JMC 14 - August 2014

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