  Physical properties of two-dimensional van der Waals (vdWs) structures depend
sensitively on both stacking orders and interlayer interactions. Yet, in most
cases studied to date, the interlayer interaction is considered to be a static
property of the vdWs structures. Here we demonstrate that applying a scanning
tunneling microscopy (STM) tip pulse on twisted bilayer graphene (TBG) can
induce sub-Angstrom fluctuations of the interlayer separation in the TBG, which
are equivalent to dynamic vertical external pressure of about 10 GPa on the
TBG. The sub-Angstrom fluctuations of the interlayer separation result in large
oscillations of the two van Hove singularities (VHSs) in the TBG. The period of
the VHSs oscillations is extremely long, about 500-1000 seconds, attributing to
the atomic-thick-film nature of the TBG. Our result provides an efficient
method to tune and measure the physical properties of the vdWs structures
dynamically.
