Strong slip-induced anomalous enhancement and red-shifts in wide-range optical absorption of graphite under uniaxial pressure

Natural graphite shows little optical response. Based on first-principles calculations, we demonstrate, for the first time, that an in-plane pressure-induced slip between atomic layers causes a strong anomalous enhancement and large red-shifts in the infrared and far infrared optical absorption by graphite. Specifically, a slip along the armchair direction induces an absorption feature that redshifts from ∼ 3 eV to ∼ 0.15 eV, while its intensity increases by an order of magnitude, due to an electron density delocalization effect with slip. Our results provide a way to detect and measure the magnitude of the in-plane slip of graphite under compression and also open up potential applications in electronics and photonics.