Trends in Bandgap of Epitaxial $\textit{A}$$_2$$\textit{B}$$_2$O$_7$ ($\textit{A}$ = Sn, Pb; $\textit{B}$ = Nb, Ta) Films Fabricated by Pulsed Laser Deposition

Abstract

Pyrochlore oxides A 2 B 2 O 7 have been a fruitful playground for condensed matter physics because of the unique geometry in the crystal structure. Especially focusing on the A-site tetrahedral sub-lattice in particular pyrochlore oxides A 2 B 2 O 7 (A = Sn, Pb; B = Nb, Ta), recent theoretical studies predict the emergence of "quasi-flat band" structure as a result of the strong hybridization between filled A-ns and O-2p orbitals. In this work, we have established the growth conditions of Sn