Fig. 5
SHG measurements on ultrathin CaTiO3 films. a Schematic of far-field transmission optical second harmonic generation (SHG) setup. Linear polarized fundamental λ = 800 nm, with polarization direction described by φ is incident onto the sample at an angle θ. Transmitted s-/p-polarized SHG signal E2ω,s, E2ω,p at λ = 400 nm is measured. b Temperature dependent SHG signal of CaTiO3 on NdGaO3, DyScO3, and LSAT reveals Curie temperature TC of 200, 350, and >900 K, respectively. c Polarimetry signal I2ω,s (red dots), I2ω,p (blue dots) on CaTiO3/NdGaO3 at 30 K are shown. Two sample orientations, O1 and O2, are experimentally measured as described by (S1, S2, S3) under orthorhombic notation. Theory fits (black lines) reveals a single domain m symmetry of the CaTiO3 on NdGaO3 at 30 K
