The optical conductivity (σ1) of SrTiO3 for various vacancies has been systematically studied using a combination of ultraviolet-vacuum ultraviolet reflectivity and spectroscopic ellipsometry. For cation (Ti) vacancies, σ1 shows large spectral weight transfer over a wide range of energy from as high as 35 eV to as low as 0.5 eV and the presence of mid-gap states, suggesting that strong correlations play an important role. Meanwhile, for anion (O) vacancies, σ1 shows changes from 7.4 eV up to 35 eV.

1.
J. B.
Goodenough
,
Localized to Itinerant Electronic Transitions in Perovskite Oxides
, Structure and Bonding Vol. 98 (
Springer
,
New York
,
2001
).
2.
C.
Lee
,
J.
Destry
, and
J. L.
Brebner
,
Phys. Rev. B
11
,
2299
(
1975
).
3.
H. P. R.
Frederikse
,
W. R.
Thurber
, and
R.
Hosier
,
Phys. Rev.
134
,
A442
(
1964
).
4.
H.
Uwe
and
T.
Sakudo
,
Phys. Rev. B
13
,
271
(
1976
).
5.
K. A.
Müller
and
H.
Burkard
,
Phys. Rev. B
19
,
3593
(
1979
).
6.
J. H.
Haeni
 et al,
Nature
430
,
758
(
2004
).
7.
J. F.
Schooley
,
W. R.
Hosler
, and
M. L.
Cohen
,
Phys. Rev. Lett.
12
,
474
(
1964
).
8.
P.
Calvani
,
M.
Capizzi
,
F.
Donato
,
S.
Lupi
,
P.
Maselli
, and
D.
Peschiaroli
,
Phys. Rev. B
47
,
8917
(
1993
).
9.
A.
Ohtomo
and
H. Y.
Hwang
,
J. Appl. Phys.
102
,
083704
(
2007
).
10.
J. L. M.
van Mechelen
,
D.
van der Marel
,
C.
Grimaldi
,
A. B.
Kuzmenko
,
N. P.
Armitage
,
N.
Reyren
,
H.
Hagemann
, and
I. I.
Mazin
,
Phys. Rev. Lett.
100
,
226403
(
2008
).
11.
H.
Eskes
,
M. B. J.
Meinders
, and
G. A.
Sawatzky
,
Phys. Rev. Lett.
67
,
1035
(
1991
).
12.
Y.
Ohta
,
K.
Tsutsui
,
W.
Koshibae
,
T.
Shimozato
, and
S.
Maekawa
,
Phys. Rev. B
46
,
14022
(
1992
).
13.
M. B. J.
Meinders
,
H.
Eskes
, and
G. A.
Sawatzky
,
Phys. Rev. B
48
,
3916
(
1993
).
14.
A.
Rusydi
 et al,
Phys. Rev. B
78
,
125110
(
2008
).
15.
I.
Santoso
 et al,
Phys. Rev. B
84
,
081403
R
(
2011
).
16.
17.
K.
van Benthem
,
R. H.
French
, and
C.
Elsässer
,
J. Appl. Phys.
90
,
6156
(
2001
).
18.
R.
Moos
and
K. H.
Härdtl
,
J. Am. Ceram. Soc.
80
,
2549
(
1997
).
19.
B. L.
Henke
,
E. M.
Gullikson
, and
J. C.
Davis
,
At. Data Nucl. Data Tables
54
,
181
(
1993
).
20.
See supplementary material at http://dx.doi.org/10.1063/1.4878675 for the details of the sample preparation and characterizations, optical measurements and analysis, and theoretical calculations.
21.
T.
Tanaka
,
K.
Matsunaga
,
Y.
Ikuhara
, and
T.
Yamamoto
,
Phys. Rev. B
68
,
205213
(
2003
).
22.
A. E.
Paladino
,
L. G.
Rubin
, and
J. S.
Waugh
,
J. Phys. Chem. Solids
26
,
391
(
1965
).
23.
L. F.
Mattheiss
,
Phys. Rev. B
6
,
4718
(
1972
).
24.
S.
Elliatioglu
and
T.
Wolfram
,
Phys. Rev. B
15
,
5909
(
1977
).
25.
P.
Pertosa
and
F. M.
Michel-Calendini
,
Phys. Rev. B
17
,
2011
(
1978
).
26.
B.
Reihl
,
J. G.
Bednorz
,
K. A.
Müller
,
Y.
Jugnet
,
G.
Landgren
, and
J. F.
Morar
,
Phys. Rev. B
30
,
803
(
1984
).
27.
F. M. F.
de Groot
,
M.
Grioni
,
J. C.
Fuggle
,
J.
Ghizsen
,
G. A.
Sawatzky
, and
H.
Petersen
,
Phys. Rev. B
40
,
5715
(
1989
).
28.
S.
Kohiki
,
M.
Arai
,
H.
Yoshikawa
,
S.
Fukushima
,
M.
Oku
, and
Y.
Waseda
,
Phys. Rev. B
62
,
7964
(
2000
).
29.
L.
Sponza
,
V.
Véniard
,
F.
Sottile
,
C.
Giorgetti
, and
L.
Reining
,
Phys. Rev. B
87
,
235102
(
2013
).
30.
S. X.
Zhang
,
S. B.
Ogale
,
W. Q.
Yu
,
X. Y.
Gao
,
T.
Liu
,
S.
Ghosh
,
G. P.
Das
,
A. T. S.
Wee
,
R. L.
Greene
, and
T.
Venkatesan
,
Adv. Mater.
21
,
2282
(
2009
).
31.
A. R.
Barman
 et al,
Appl. Phys. Lett.
98
,
072111
(
2011
).
32.
A.
Rusydi
 et al,
Philos. Trans. R. Soc. A
370
,
4927
(
2012
).
33.
D.
Qi
 et al,
Phys. Rev. B
87
,
245201
(
2013
).

Supplementary Material

You do not currently have access to this content.