Modulation of a semicondutor-to-semimetal transition at 7 THz via coherent lattice vibrations

This letter introduces the general notion of significantly modulating the physical characteristics of a solid on a terahertz time scale with coherent lattice vibrations. We show, as an example, experiments in which coherent phonons are optically excited in single-crystal Ti2O3, which is a narrow-gap semiconductor at 300 K and gradually transforms into a semimetal at 600 K. Quantitative comparison of previous equilibrium measurements to our new transient measurements suggests that the induced coherent lattice vibration is significantly modulating the semiconductor-to-semimetal transition at 7 THz.