Filters

2018 - 201912020 - 20211

More filters

2019 - 201912020 - 20221
Reset filters

Settings

Author: Artyukhin, Sergey ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Ultrafast dissolution and creation of bonds in IrTe2 induced by photodoping
    (Washington, DC : American Association for the Advancement of Science, 2018) Ideta, Shin-ichiro; Zhang, Dongfang; Dijkstra, Arend G; Artyukhin, Sergey; Keskin, Sercan; Cingolani, Roberto; Shimojima, Takahiro; Ishizaka, Kyoko; Ishii, Hiroyuki; Kudo, Kazutaka; Nohara, Minoru; Miller, R.J. Dwayne
    The observation and control of interweaving spin, charge, orbital, and structural degrees of freedom in materials on ultrafast time scales reveal exotic quantum phenomena and enable new active forms of nanotechnology. Bond- ing is the prime example of the relation between electronic and nuclear degrees of freedom. We report direct evidence illustrating that photoexcitation can be used for ultrafast control of the breaking and recovery of bonds in solids on unprecedented time scales, near the limit for nuclear motions. We describe experimental and theoretical studies of IrTe2 using femtosecond electron diffraction and density functional theory to investigate bonding instability. Ir-Ir dimerization shows an unexpected fast dissociation and recovery due to the filling of the antibonding dxy orbital. Bond length changes of 20% in IrTe2 are achieved by effectively addressing the bonds directly through this relaxation process. These results could pave the way to ultrafast switching between metastable structures by photoinduced manipulation of the relative degree of bonding in this manner.
  • Thumbnail Image
    Item
    Phase Transitions in Low-Dimensional Layered Double Perovskites: The Role of the Organic Moieties
    (Washington, DC : ACS, 2021) Martín-García, Beatriz; Spirito, Davide; Biffi, Giulia; Artyukhin, Sergey; Francesco Bonaccorso, null; Krahne, Roman
    Halide double perovskites are an interesting alternative to Pb-containing counterparts as active materials in optoelectronic devices. Low-dimensional double perovskites are fabricated by introducing large organic cations, resulting in organic/inorganic architectures with one or more inorganic octahedra layers separated by organic cations. Here, we synthesized layered double perovskites based on 3D Cs2AgBiBr6, consisting of double (2L) or single (1L) inorganic octahedra layers, using ammonium cations of different sizes and chemical structures. Temperature-dependent Raman spectroscopy revealed phase transition signatures in both inorganic lattice and organic moieties by detecting variations in their vibrational modes. Changes in the conformational arrangement of the organic cations to an ordered state coincided with a phase transition in the 1L systems with the shortest ammonium moieties. Significant changes of photoluminescence intensity observed around the transition temperature suggest that optical properties may be affected by the octahedral tilts emerging at the phase transition.