Light control of unconventional charge transport
Sheng Meng (Institute of Physics, Chinese Academy of Science)
Email: smeng@iphy.ac.cn
Light control of unconventional charge transport
Sheng Meng (Institute of Physics, Chinese Academy of Science)
Email: smeng@iphy.ac.cn
Photoexcitation is a powerful means in distinguishing different interactions and manipulating the properties of matter, especially for charge transport and phase transitions in complex quantum systems.
Here we show that laser-controlled coherent phonon excitation can drastically promote K-to-Q intervalley charge transfer transition within sub-picoseconds in WSe2. This coherent-phonon-driven intervalley scattering occurs in an unconventional steplike manner and further induces an electronic Rabi oscillation. We also find that laser-controlled coherent phonons enable orders of magnitude enhancement of carrier mobility via accelerating polaron transport in a prototypical material lithium peroxide. The selective excitation of specific phonon modes, whose vibrational pattern directly overlap with the polaronic lattice deformation, can remarkably reduce the energy barrier for polaron hopping. The strong nonadiabatic couplings between the electronic and ionic subsystem play a key role in triggering charge transport. These results extend our understanding of charge transport dynamics to the unconventional nonequilibrium regime and allow for optoelectronic devices with ultrahigh on-off ratio and ultrafast responsibility competitive with those of state-of-the-art devices. We also investigate photoexcitation induced ultrafast phase-transition dynamics in materials that is significantly different from thermal phase transitions. Our results provide insights from a new perspective on the coherent electron and lattice quantum dynamics in materials upon photoexcitation.
References:
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5. Z.W. Nie, Y.X. Wang, D.Q. Chen, S. Meng. Unraveling hidden charge density wave phases in 1T-TiSe2. Phys. Rev. Lett. 131, 196401 (2023).
6. M.X. Guan, D.Q. Chen, Q. Chen, Y.G. Yao, S. Meng. Coherent Phonon Assisted Ultrafast Order-Parameter Reversal and Hidden Metallic State in Ta2NiSe. Phys. Rev. Lett. 131, 256503 (2023).