Abstract
First-principles calculations are used to study KNbO3:Y ultrathin film. The conducting two-dimensional electron gas (2DEG) is found in KNbO3:Y film, whereas SrTiO3:Y superlattice is insulating [Science 331, 886 (2011)]. The carrier density of 2DEG of KNbO3:Y film is twice that of LaTiO3/SrTiO3 superlattice, which is in agreement with the theoretical results of KNbO3:La superlattice. It is found that the charge densities of different monolayers are modulated by the polarization effect of KNbO3. We predict that 2DEG may be in other rare-earth atoms-doped KNbO3 film.
Similar content being viewed by others
References
Ohtomo A, Hwang HY (2004) A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface. Nature 427:423–426
Okamoto S, Millis AJ (2004) Electronic reconstruction at an interface between a mott insulator and a band insulator. Nature 428:630–633
Jang HW, Felker DA, Bark CW, Wang Y, Niranjan MK, Nelson CT, Zhang Y, Su D, Folkman CM, Baek SH, Lee S, Janicka K, Zhu Y, Pan XQ, Fong DD, Tsymbal EY, Rzchowski MS, Eom CB (2011) Metallic and insulating oxide interfaces controlled by electronic correlations. Science 331:886–889
Hwang HY, Iwasa Y, Kawasaki M, Keimer B, Nagaosa N, Tokura Y (2012) Emergent phenomena at oxide interfaces. Nature Mater 11:103–113
Popović ZS, Satpathy S, Martin RM (2008) Origin of the two-dimensional electron gas carrier density at the LaAlO3 on SrTiO3 interface. Phys Rev Lett 101:256801
Janicka K, Velev JP, Tsymbal EY (2009) Quantum nature of two-dimensional electron gas confinement at LaAlO3/SrTiO3 interfaces. Phys Rev Lett 102:106803
Niranjan MK, Wang Y, Jaswal SS, Tsymbal EY (2009) Prediction of a switchable two-dimensional electron gas at ferroelectric oxide interfaces. Phys Rev Lett 103:016804
Verissimo-Alves M, García-Fernández P, Bilc DI, Ghosez P, Junquera J (2012) Highly confined spin-polarized two-dimensional electron gas in SrTiO3/SrRuO3 superlattices. Phys Rev Lett 108:107003
Cooper VR (2012) Enhanced carrier mobilities in two-dimensional electron gases at III–III/I-V oxide heterostructure interfaces. Phys Rev B 85:235109
Bark CW, Sharma P, Wang Y, Baek SH, Lee S, Ryu S, Folkman CM, Paudel TR, Kumar A, Kalinin SV, Sokolov A, Tsymbal EY, Rzchowski MS, Gruverman A, Eom CB (2012) Switchable induced polarization in LaAlO3/SrTiO3 heterostructures. Nano Lett 12:1765–1771
Moon SY, Kim D-H, Chang HJ, Choi JK, Kang C-Y, Choi HJ, Hong S-H, Baek S-H, Kim J-S, Jang HW (2013) Tunable conductivity at LaAlO3/SrxCa1-xTiO3 (0 ≤ x ≤ 1)) heterointerfaces. Appl Phys Lett 102:012903
Nazir S, Schwingenschlögl U (2013) Strain effects on the spin polarized electron gas in ABO3/SrTiO3 (A = Pr, Nd and B = Al, Ga) heterostructures. Appl Phys Lett 102:141604
Lechermann F, Boehnke L, Grieger D (2013) Formation of orbital-selective electron states in LaTiO3/SrTiO3 superlattices. Phys Rev B 87:241101(R)
Eglitis RI, Kotomin EA, Borstel G, Dorfman S (1998) Semi-empirical calculations of the Nb-ion positions in doped KTaO3 crystals. J Phys: Condens Matter 10:6271–6276
Eglitis RI, Kotomin EA, Borstel G (2000) Quantum chemical modelling of perovskite solid solutions. J Phys: Condens Matter 12:L431–L434
Sai N, Kolpak AM, Rappe AM (2005) Ferroelectricity in ultrathin perovskite films. Phys Rev B 72:020101(R)
Clark SJ, Segall MD, Pickard CJ, Hasnip PJ, Probert MJ, Refson K, Payne MC (2005) First principles methods using CASTEP. Z Kristallogr 220:567–570
Wu Z, Cohen RE (2006) More accurate generalized gradient approximation for solids. Phys Rev B 73:235116
Vanderbilt D (1990) Soft self-consistent pseudopotentials in a generalized eigenvalue formalism. Phys Rev B 41:7892(R)
Seidl A, Görling A, Vogl P, Majewski JA, Levy M (1996) Generalized Kohn-Sham schemes and the band-gap problem. Phys Rev B 53:3764
Gillen R, Robertson J (2012) Hybrid functional calculations of the Al impurity in α quartz: Hole localization and electron paramagnetic resonance parameters. Phys Rev B 85:014117
Shen Y, Zhou Z (2008) The effects of the doped Cu on the physical properties of KNbO3 crystal. Chem Phys Lett 454:114–117
Okamoto S, Millis AJ, Spaldin NA (2006) Lattice relaxation in oxide heterostructures: LaTiO3/SrTiO3 superlattices. Phys Rev Lett 97:056802
King PDC, He RH, Eknapakul T, Buaphet P, Mo S-K, Kaneko Y, Harashima S, Hikita Y, Bahramy MS, Bell C, Hussain Z, Tokura Y, Shen Z-X, Hwang HY, Baumberger F, Meevasana W (2012) Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite. Phys Rev Lett 108:117602
Acknowledgements
The research is supported by National Natural Science Foundation of China (Nos.11204053 and 11074059) and the China Postdoctoral Science Foundation (Grant No. 2013M531028). We would like to thank High Performance Computing Center of Harbin Institute of Technology for the help of the calculation.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Shen, Y., Wang, W., Zhou, Z. et al. Two-dimensional electron gas in the KNbO3:Y ultrathin film. J Mater Sci 50, 74–78 (2015). https://doi.org/10.1007/s10853-014-8567-7
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10853-014-8567-7