Direct spectroscopic observation of a shallow hydrogen-like donor state in insulating SrTiO${}_3$

Abstract

We present a direct spectroscopic observation of a shallow hydrogen-like muonium state in SrTiO${}_3$ which confirms the theoretical prediction that interstitial hydrogen may act as a shallow donor in this material. The formation of this muonium state is temperature dependent and appears below $\sim 70$ K. From the temperature dependence we estimate an activation energy of $\sim 50$ meV in the bulk and $\sim 23$ meV near the free surface. The field and directional dependence of the muonium precession frequencies further supports the shallow impurity state with a rare example of a fully anisotropic hyperfine tensor. From these measurements we determine the strength of the hyperfine interaction and propose that the muon occupies an interstitial site near the face of the oxygen octahedron in SrTiO${}_3$. The observed shallow donor state provides new insight for tailoring the electronic and optical properties of SrTiO${}_3$-based oxide interface systems.

6 pages, 4 figures. To appear in Phys. Rev. Lett

References in corpus (5)

• Magnetic effects at the interface between nonmagnetic oxides
• Photoemission from buried interfaces in SrTiO3/LaTiO3 superlattices
• Lattice polarization effects on electron-gas charge densities in ionic superlattices
• Nature of weak magnetism in SrTiO3/LaAlO3 multilayers
• Formation of hydrogen impurity states in silicon and insulators at low implantation energies

Cited by in corpus (12)

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• Ambipolar Property of Isolated Hydrogen in Oxide Materials Revealed by Muon
• Polaronic nature of a muonium-related paramagnetic center in SrTiO${}_3$
• Depth dependence of the ionization energy of shallow hydrogen states in ZnO and CdS
• Magnetic order of tetragonal CuO ultra-thin films
• Negatively Charged Muonium and Related Centers in Solids
• Small sample measurements at the low energy muon facility of Paul Scherrer Institute
• Hydrogen-Ti${}^{3+}$ Complex as a Possible Origin of Localized Electron Behavior in Hydrogen-Irradiated SrTiO${}_3$
• Local electronic structure of dilute hydrogen in $\beta$-MnO${}_2$
• Probing current-induced magnetic fields in Au|YIG heterostructure with low-energy muon spectroscopy
• Muon spin relaxation in mixed perovskite (LaAlO${}_3$)${}_x$(SrAl${}_{0.5}$Ta${}_{0.5}$O${}_3$)${}_{1-x}$ with $x\simeq 0.3$
• Correcting the Energy-Dependent Asymmetry in Low-Energy $\mu$SR