title: Second harmonic generation in carbon nanotubes induced by transversal electrostatic field.
abstract: Carbon nanotubes (CNTs) of armchair and zigzag type contain an inversion centre, and are thus intrinsically unable to generate dipole even-order nonlinearities, such as second harmonic generation (SHG). Breaking the inversion symmetry by application of an external voltage transversal to the CNT axis will, however, induce a second harmonic response. Similarly, additional non-vanishing second harmonic tensor elements will be induced in chiral tubes already displaying an intrinsic response. Many geometries realizing such a setup can be envisaged, e.g., an experimental gate setup or deposition of CNTs on, or integration in, strongly polarized host media, perhaps facilitating a tunable second harmonic response. In this work, we calculate the SHG signal from CNTs under transversally applied electric fields based on a tight-binding model.
authors.affiliation: Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4A, DK-9220 Aalborg East, Denmark. mlt@nano.aau.dk
authors.forename: Mads Lund
authors.initials: ML
authors.lastname: Trolle
authors.forename: Thomas Garm
authors.initials: TG
authors.lastname: Pedersen