Author(s): Liu, HW (Liu, Hao-Wen); Liu, WH (Liu, Wen-Hao); Suo, ZJ (Suo, Zhao-Jun); Wang, Z (Wang, Zhi); Luo, JW (Luo, Jun-Wei); Li, SS (Li, Shu-Shen); Wang, LW (Wang, Lin-Wang)

Source: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Volume: 119 Issue: 28 Article Number: e2122534119 DOI: 10.1073/pnas.2122534119 Published: JUL 12 2022

Abstract: Photoinduced phase transition (PIPT) is always treated as a coherent process, but ultrafast disordering in PIPT is observed in recent experiments. Utilizing the real-time time-dependent density functional theory method, here we track the motion of individual vanadium (V) ions during PIPT in VO2 and uncover that their coherent or disordered dynamics can be manipulated by tuning the laser fluence. We find that the photoexcited holes generate a force on each V-V dimer to drive their collective coherent motion, in competing with the thermal-induced vibrations. If the laser fluence is so weak that the photoexcited hole density is too low to drive the phase transition alone, the PIPT is a disordered process due to the interference of thermal phonons. We also reveal that the photoexcited holes populated by the V-V dimerized bonding states will become saturated if the laser fluence is too strong, limiting the timescale of photoinduced phase transition.

Accession Number: WOS:000854977600002

PubMed ID: 35867737

Author Identifiers:

Author        Web of Science ResearcherID        ORCID Number

Wang, Lin-Wang                  0000-0001-7061-2692

Liu, Wenhao                  0000-0002-2385-2172

ISSN: 0027-8424

eISSN: 1091-6490

Full Text: https://pnas.org/doi/full/10.1073/pnas.2122534119