Coulomb Interaction Engineering at YBa$$_{2}$$Cu$$_3$$O$$_{7-\delta }$$-SrTiO$$_{3}$$ Interface

Abstract

AbstractIt has been proposed by Müller and Shengelaya that underdoped ultrathin layers of copper-oxide high-temperature superconductors (HTSs) sandwiched between high-dielectric-constant insulator layers could manifest increased superconducting critical temperature $$T_c$$ T c . To check this hypothesis, we investigated structural and transport properties of YBa$$_{2}$$ 2 Cu$$_{3}$$ 3 O$$_{7-\delta }$$ 7 - δ (YBCO) thin films sandwiched between SrTiO$$_{3}$$ 3 (STO) layers. Scanning transmission electron microscopy (STEM) showed that a high-quality interface is formed between YBCO and the top STO layers. An increase of $$T_c$$ T c up to $$\Delta$$ Δ T$$\approx$$ ≈ 20 K was observed at these interfaces in case of underdoped YBCO films.