  Elemental tellurium is a strongly spin-orbit coupled Peierls-distorted
semiconductor whose band structure features topologically protected Weyl nodes.
Using time-dependent density functional theory calculations, we show that
impulsive optical excitation can be used to transiently control the amplitude
of the Peierls distortion, realizing a mechanism to switch tellurium between
three states: Weyl semiconductor, Weyl metal and non-Weyl metal. Further, we
present experimental evidence of this inverse-Peierls distortion using
time-resolved optical second harmonic generation measurements. These results
provide a pathway to multifunctional ultrafast Weyl devices and introduce
Peierls systems as viable hosts of light-induced topological transitions.

Strongly Correlated Electrons;Mesoscale and Nanoscale Physics;Materials Science