Regensburg 2022 – scientific programme
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O: Fachverband Oberflächenphysik
O 9: Ultrafast Electron Dynamics at Surfaces and Interfaces 2
O 9.5: Talk
Monday, September 5, 2022, 16:00–16:15, H3
Coherent Control of a Metastable Hidden Phase — J. Maklar1, S. Dong1, •J. Sarkar1, Y. A. Gerasimenko2, T. Pincelli1, S. Beaulieu1, P. S. Kirchmann3, J. A. Sabota3, S.-L. Yang3,4, D. Leuenberger3,4, R. G. Moore3, Z.-X. Shen3,4, M. Wolf1, D. Mihailovic2, R. Ernstorfer1,5, and L. Rettig1 — 1Fritz-Haber-Institut der MPG, Berlin, DE — 2Jožef Stefan Institute, Jubljana, Sl — 3SLAC National Accelerator Laboratory, California, USA — 4Stanford University, California, USA — 5Technical University Berlin, DE
In materials with multiple competing orders, ultrashort light pulses can induce metastable states that are not accessible at thermodynamic equilibrium. One of such, the metallic hidden (H) phase of 1T-TaS2, is of particular interest as it features an order-of-magnitude change in resistivity, promising for novel energy-efficient high-speed memory devices. We use time- and angle-resolved photoemission spectroscopy (trARPES) to investigate the electronic band structure and formation dynamics of the metastable H-state in 1T-TaS2. The band structure mapping of H-state reveals suppression of correlation effects and metallization, suggesting a critical role of interlayer stacking order of the TaS2 sheets in the phase transition. The fluence-dependent dynamics provides strong evidence that the charge density wave amplitude mode governs a collective, ultrafast switching pathway to the H-state. This is further corroborated by demonstrating coherent control of the switching efficiency into the H-phase using a multi-pump-pulse excitation scheme.