Interaction of crystalline topological insulator with an ultrashort laser pulse

Abstract

We study theoretically interaction of crystalline topological insulator (CTI), characterized by surface quadratic gapless bands, with an ultrashort (few-femtosecond) optical pulse. The electron dynamics in such an optical pulse is determined by a strong lattice-momentum dependence of the interband dipole coupling, which is anisotropic and singular at the degeneracy point. The interband mixing induced by the ultrashort pulse results in a finite conduction band population, the distribution of which in the reciprocal space is correlated with the profile of the interband dipole matrix elements and has high contrast. The number of such high contrast regions depends on the polarization direction of the optical pulse. The ultrashort pulse also causes an electrical current and a net charge transfer through the system in the direction of the maximum field. These findings open up roots to ultrafast optical-field control of the TCI's and petahertz-band opto-electronics

Strong-field physics in three-dimensional topological insulators

“…In fact, the presence of imaginary components in d cv (k ∥ ) is a characteristic feature of TSSs in 3D-TIs that is distinctly different than other gapless systems with linear dispersion, such as graphene, as elaborated in Refs. [30,31]. We now show that this feature is mediated by the strong spin-orbit coupling in the 3D-TI system, and that it gives rise to the pronounced anomalous ellipticity behavior of the higher orders.…”

“…In contrast to the k ⋅ p-perturbative model [43] frequently employed to study the low-energy physics of 3D-TIs (s. Refs. [30,31]), the TBM Hamiltonian defined in Eq. ( 3) retains its validity over the entire Brillouin zone and is periodic.…”

“…Owing to these properties, TIs represent a potentially unique platform to control and manipulate strong-field-driven dynamics, including those leading to HHG. In this context, 3D-TIs were theoretically shown to support sub-cycle chiral electron dynamics originating from the chirality of Bloch bands near the Gamma point and "hexagonal warping" [30,31]. It has further been predicted that the topological properties of materials [32] can be controlled and manipulated through interactions with strong circularly polarized laser fields.…”

Ultrafast electron dynamics in monolayer MoS2 interacting with optical pulse influenced by exchange field and waveform

“…The interaction of an ultrafast optical pulse with solids has been the valuable topic of intensive theoretical and experimental works over the last few years [1][2][3][4][5][6][7][8][9][10][11][12][13]. It contains rich information about electronic structure, optical control and optical probing of electron dynamics in materials at a femtosecond time scale.…”

Femtosecond valley polarization and topological resonances in transition metal dichalcogenides

“…Based on this, we describe the electron dynamics as coherent by time-dependent Schrödinger equation (TDSE). Previously, such a TDSE theory [41][42][43][44][45][46][47][48][49] was successful in predicting new effects and describing expermental results in both three-dimensional solids 2,3,50 and graphene 51 . For non-interacting particles, the TDSE theory is fundamentally equivalent to the density matrix equations but is computationally much more efficient.…”