报告题目:Light control ofunconventional chargetransport
摘要(点击查看)
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-controlledcoherent phonons enable orders of
magnitude enhancement of carrier mobility via accelerating
polaron transport in a prototypical material lithium
peroxide. The selective excitationof 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.
简介(点击查看)
孟胜,男,中科院物理所研究员、国科大岗位教授、表面物理
国家重点实验室主任。国家杰出青年科学基金获得者,
国家重点研发计划项目首席科学家。
2000 年中国科技大学毕业,2004 年获中科院物理所凝聚态物理
博士学位,同年获瑞典Chalmers 理工大学应用物理博士学位。
2005-2009年在哈佛大学物理系任博士后。2009年7月回国任
特聘研究员。现任研究员、课题组长、国家重点实验室主任。