Epitaxial growth and transport properties of Nb-doped SrTiO${}_3$ thin films

Abstract

Nb-doped SrTiO${}_3$ epitaxial thin films have been prepared on (001) SrTiO${}_3$ substrates using pulsed laser deposition. A high substrate temperature ($>1000^{\circ }C$) was found to be necessary to achieve 2-dimensional growth. Atomic force microscopy reveals atomically flat surfaces with 3.9 Å steps. The films show a metallic behavior, residual resistivity ratios between 10 and 100, and low residual resistivity of the order of 10${}^{-4}$$\Omega$cm. At 0.3 K, a sharp superconducting transition, reaching zero resistance, is observed.

4 pages, 4 figures