Supporting Information for
Epitaxial Thin Films of ATiO3-xHx (A = Ba, Sr, Ca) with
Metallic Conductivity
Takeshi Yajima1, Atsushi Kitada1, Yoji Kobayashi1, Tatsunori Sakaguchi1, Guillaume Bouilly, Shigeru
Kasahara2, Takahito Terashima2, Mikio Takano3, Hiroshi Kageyama1, 3*
1 Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto
615-8510, Japan
2 Research Center for Low Temperature and Materials Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
3 Institute for Integrated Cell-Material Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
[email protected]
Table S1. The changes of out-of-plane lattice parameters (∆c) from the as-grown films were shown. Both CaH2
treatment and annealing under vacuum without CaH2 was performed at 530 °C for 1day.
BaTiO3/LSAT (Å)
SrTiO3/LSAT (Å)
CaTiO3/LSAT (Å)
CaH2 treatment
-0.008
-0.015
0.018
Annealing under Vac.
0.005
-0.002
0.005
S1
Figure S1. Out-of-plane XRD pattern of (a) as grown BaTiO3/LSAT film, (b) BaTiO3/LSAT film after
CaH2-reduction at 530 °C for 1 day, (c) as grown CaTiO3/LSAT film, (b) CaTiO3/LSAT film after CaH2-reduction
at 530 °C for 1 day. Insets are enlarged view of ATiO3 (001) reflection and LSAT (002) reflection showing the
c-axis decrease and increase for BaTiO3/LSAT and for CaTiO3/LSAT, respectively, after hydride treatment.
S2
Figure S2. Out-of-plane XRD pattern of (a) as grown SrTiO3/LSAT film, (b) SrTiO3/LSAT film after
CaH2-reduction at 300 °C for 1 day. Inset is the enlarged view of SrTiO3 (001) reflection and LSAT (002)
reflection showing the c-axis decrease of the reduced SrTiO3/LSAT thin film.
(a)
S3
(b)
Figure S3. (a) Dynamic-SIMS depth profile of H, Ba, Ti, O secondary ion in the BaTiO3/LSAT film reduced at
530 °C for 1 day. (b). Dynamic-SIMS depth profile of H, Ca, Ti, O secondary ion in the CaTiO3/LSAT film
reduced at 530 °C for 1 day. Secondary ion intensity of hydrogen was converted to density by using standard
sample of SrTiO3. In the reduced CaTiO3/LSAT film, the Ca secondary ion intensity was obtained based on the
40
Ca signal. We also probed the film using isotope 44Ca, but found different 40Ca/44Ca ratios along the depth of the
film. (There are two natural isotopes of calcium, 40Ca (97%) and 44Ca (2%).) The Ti and O signals, however, are
fairly constant near the surface, and XRD shows no signs of film inhomogeneities. Thus, we believe that the large
40
Ca signal near the surface is due to another ion interfering with the
what this is.
S4
40
Ca signal, although we are not yet sure
Figure S4. Temperature dependence of carrier density and mobility for the SrTiO2.75H0.25 film estimated from the
Hall measurements. The carrier density of 4.1×1021 at room temperature corresponds to the amount of hydride
estimated from the SIMS measurement, and is almost the same as that of 20% Nb-doped SrTiO3 (3 ~ 4×1021).
S5