Fig. 3: Room tempreture CPGE spectrum, optical conductivity and band structure for CoSi.
From: Giant topological longitudinal circular photo-galvanic effect in the chiral multifold semimetal CoSi
a Measured second-order CPGE photo-conductivity (βxxτ) as a function of incident photon energy, and ab-intio calculations of the CPGE current with and without spin-orbit coupling at room temperature. b The band structure of CoSi without spin-orbit coupling. We define zero energy at the threefold node at the Γ point. The double Weyl node at the R point is at −185 meV. The dashed horizontal line indicates the chemical potential Ef = −37 meV in our sample, moderately lower from that obtained by DFT (Ef = −20 meV). The band structure of the k ⋅ p model is shown in green (band 1), blue (band 2), and orange (band 3) obtained by fitting the ab-intio band structure (black) up to quadratic corrections. For the Γ−X direction we define \({\omega }_{1}^{X}\), \({\omega }_{2}^{X}\), and \({\omega }_{3}^{X}\) as the minimum energy that allows transitions from band 1 to band 2, the maximum energy that allows transition from band 1 to band 2 and the minimum energy that allows transitions from band 2 to band 3, respectively. We define in the same way \({\omega }_{1}^{R}\) in the R direction (\({\omega }_{2,3}^{R}\) fall outside the applicability of the quadratic model). c Total (gold) and interband (blue) optical conductivity of CoSi at 300 K. d Momentum resolved contributions to the CPGE peak at 0.4 eV in the red curve in a.
