  The self-trapped state (STS) of interlayer exciton (IX) has been aroused
enormous interesting owing to their significant impact on the fundamental
properties of the van derWaals heterostructures (vdWHs). Nevertheless, the
microscopic mechanisms of STS are still controversial. Herein, we study the
corrections of the binding energies of the IXs due to the exciton-interface
optical phonon coupling in four kinds of vdWHs and find that these IXs are in
the STS for the appropriate ratio of the electron and hole effective masses. We
show that these STSs could be classified into the type I with the increasing
binding energy in the tens of meV range, which are very agreement with the
red-shift of the IXs spectra in experiments, and the type II with the
decreasing binding energy, which provides a possible explanation for the
blue-shift and broad linewidth of the IXs spectra in the low temperature.
Moreover, these two types of self-trapped IXs could be transformed into each
other by adjusting the structural parameters of vdWHs. These results not only
provide an in-depth understanding for the self-trapped mechanism of IX, but
also shed light on the modulations of IXs in vdWHs.
