English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Ultrafast vibrational dynamics of inorganic-organic hybrid lead halideperovskite CH3NH3PbI$ in the room-temperature tetragonal phase is investigatedunder moderate photoexcitation slightly below the band gap. Time-resolvedoptical Kerr effect signal exhibits periodic modulations due to the librationand twisting of the methylammonium molecule at 4 and 8 THz, in addition to theinorganic sublattice deformation at 1.2 THz. These oscillations are heavilydamped, and their frequencies exhibit blueshifts with increasing pump density,contrary to the expectation from conventional laser heating. Our ab initiolattice dynamics simulations reveal strongly anharmonic vibrational potentialsfor the zone-center optical phonon modes, and thereby confirm the anharmonicityto be the origin of the experimentally observed frequency blueshifts.

Strongly Anharmonic Organic Cation Vibrations in Hybrid Lead Halide Perovskite CH3NH3PbI3 on Electronic Ground State