Figure 4
Electronic band structures of few-layer Ca2N and Sr2N.
a-c, Band structure of Ca2N with a 1-ML, b 2-ML and c 3-ML thickness. d-f, Band structure of Sr2N with d 1-ML, e 2-ML and f 3-ML thickness. Fermi energy is set at zero. The two green colored bands are mainly from the 2D electron layers confined to the surface. The red colored bands (for films thicker than 1-ML) are mainly from the 2D electron layers confined in the interlayer regions. The red shaded rectangles in a and d indicate the regions contributing to the peaks ~0.3 eV in interband Imε(ω) for 1-ML Ca2N and Sr2N.
