Extended Data Figure 1: Reflection high-energy electron diffraction (RHEED) images observed during FeSe growth.
From: Interfacial mode coupling as the origin of the enhancement of Tc in FeSe films on SrTiO3
a, RHEED image of SrTiO3 substrate after degassing at 450 °C for 1 h. Red box highlights the region integrated for monitoring RHEED oscillations. b, Surface reconstruction as observed by RHEED at annealing temperatures. c, RHEED image of FeSe 1UC film showing uniform streaks typical of an atomically flat thin film. d, RHEED intensity for integration region shown in a (black). The second derivative of the intensity curve (red), with numbers indicating the number of layers grown highlights the RHEED oscillations signalling the completion of a unit cell after about 30 s.
