Anisotropic Light–Matter Interaction in TiO ₂

Anisotropy has been extensively harnessed in heat control, energy harvesting, and light–matter interaction (LMI) systems. As a renowned LMI compound, the LMI anisotropy of TiO 2 has so far remained elusive. Leveraging the highlight anisotropy characters in the 2D crystal, here, we revealed an LMI anisotropy feature of the (110) plane in rutile-TiO 2 single crystal. The photoelectricity exhibits notably anisotropy, where a significantly higher current response is observed along the y -axis direction. The light absorption and irradiation enhancements have been reflected in Raman intensity variations, indicating a stronger atomic vibration significantly modulates the electron density wave function along y -axis, leading to an increase of hot electrons incoherent transport. Meanwhile, electron–phonon scattering intensifies due to the coupling between low-effective-mass electrons. Thereby, hot electrons preferentially transport along the y -axis rather than the x -axis, ultimately leading to an LMI anisotropy. Our investigation provides an intriguing insight for potential optimization in broadly light–matter reactions.