Strong light-field effects driven by nearly single-cycle 7 fs light-field in correlated organic conductors

Abstract

We have demonstrated transient charge localization effects with a driving high-frequency field of 7-fs, 1.5-cycle near infrared light in correlated organic conductors. In a layered organic conductor -(BEDT-TTF)2I3 (BEDT-TTF: bis[ethylenedithio]-tetrathiafulvalene), a transient short-range charge order (CO) state is induced in a metallic phase. In contrast to such drastic change in the electronic state from the metal to the transient CO in -(BEDT-TTF)2I3, dynamics of a field-induced reduction of a transfer integral are captured as a red shift of the plasma-like reflectivity edge in a quasi-one-dimensional organic conductor (TMTTF)2AsF6 (TMTTF: tetramethyltetrathiafulvalene). These studies on the field-induced charge localization have been motivated by the theory of dynamical localization on the basis of tight-binding models with no electron correlation under a strong continuous field. However, the results of pump-probe transient reflectivity measurements using nearly single-cycle 7-fs, 11 MV/cm pulses and the theoretical studies which are presented in this review indicate that the pulsed field contributes to the similar phenomenon with the help of a characteristic lattice structure and Coulomb repulsion.

Nonequilibrium susceptibility in photoinduced Floquet states

“…where J n is the nth-order Bessel function of the first kind, indicating the DL effect, i.e., a reduction in the electron bandwidth [8,[60][61][62][63]. We note that the circularly polarized light acts simply as an isotropic external field in the present freeelectron model where the spin-orbit coupling and the Zeeman term are not taken into account.…”

“…Recent great progress in laser light technology promotes significantly the scientific research in strongly coupled lightmatter systems. Intense and ultrashort light irradiation induces a variety of nontrivial phenomena that are not realized in thermal equilibrium such as photoinduced phase transitions [1][2][3], coherent control of spin or electronic polarization [4][5][6][7], and the dynamical localization (DL) [8]. One of the fascinating phenomena induced by the strong light-matter coupling is appearance of the Floquet states, in which a time-periodic electromagnetic field behaves as photons and hybridizes with electrons [9][10][11].…”

Symmetry-protected difference between spin Hall and anomalous Hall effects of a periodically driven multiorbital metal

“…For Sr 2 RuO 4 , in which a lc ≈ 0.39 nm 35 , u(= ea lc A 0 ) = 0.3 at Ω = 2, 4, or 6 eV corresponds to E 0 = A 0 /Ω ≈ 15, 31, or 46 MVcm −1 , respectively. Since the pump field of the order of 10 MVcm −1 is experimentally accessible 52 , we conclude that the predicted properties of σ S yx and σ C yx could be observed in the pump-probe measurements of the SHE and AHE in periodically driven Sr 2 RuO 4 .…”

Photoinduced Pseudospin Polarization in a Three-Orbital Hubbard Model

“…Photoinduced cooperative phenomena, including photoinduced phase transitions, have attracted considerable attention. [1][2][3][4][5][6][7][8][9][10][11] For those accompanied by a symmetry change, its mechanisms have been a central issue. If the transition is between metastable and stable phases, photoexcitations produce seeds of fluctuations that grow under some conditions.…”