We have noticed a mistake in reporting the XPS peak energies of Hf 4f5/2 and 4f7/2 from oxide layers at line 28 of page 2.1 The values should be corrected to be 20 and 18 eV for Hf 4f5/2 and 4f7/2, respectively. This correction does not change the interpretation of the results.

1.
H. R.
Kim
,
J.
Ohta
,
S.
Inoue
,
K.
Ueno
,
A.
Kobayashi
, and
H.
Fujioka
,
APL Mater.
4
,
076104
(
2016
).