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# Electronic reconstruction at an interface between a Mott insulator and a band insulator

## Abstract

Surface science is an important and well-established branch of materials science involving the study of changes in material properties near a surface or interface. A fundamental issue has been atomic reconstruction: how the surface lattice symmetry differs from the bulk. ‘Correlated-electron compounds’ are materials in which strong electron–electron and electron–lattice interactions produce new electronic phases, including interaction-induced (Mott) insulators, many forms of spin, charge and orbital ordering, and (presumably) high-transition-temperature superconductivity1,2. Here we propose that the fundamental issue for the new field of correlated-electron surface/interface science is ‘electronic reconstruction’: how does the surface/interface electronic phase differ from that in the bulk? As a step towards a general understanding of such phenomena, we present a theoretical study of an interface between a strongly correlated Mott insulator and a band insulator. We find dramatic interface-induced electronic reconstructions: in wide parameter ranges, the near-interface region is metallic and ferromagnetic, whereas the bulk phase on either side is insulating and antiferromagnetic. Extending the analysis to a wider range of interfaces and surfaces is a fundamental scientific challenge and may lead to new applications for correlated electron materials.

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## References

1. Imada, M., Fujimori, A. & Tokura, Y. Metal-insulator transitions. Rev. Mod. Phys. 70, 1039–1263 (1998)

2. Tokura, Y. & Nagaosa, N. Orbital physics in transition-metal oxides. Science 288, 462–468 (2000)

3. Altieri, S., Tjeng, L. H. & Sawatzky, G. A. Ultrathin oxide films on metals: new physics and new chemistry? Thin Solid Films 400, 9–15 (2001)

4. Hesper, R., Tjeng, L. H., Heeres, A. & Sawatzky, G. A. Photoemission evidence of electronic stabilization of polar surface in K3C60 . Phys. Rev. B 62, 16046–16055 (2000)

5. Duffy, D. M. & Stoneham, A. M. Conductivity and ‘negative U’ for ionic grain boundaries. J. Phys. C 16, 4087–4092 (1983)

6. Altieri, S., Tjeng, L. H. & Sawatzky, G. A. Electronic structure and chemical reactivity of oxide-metal interfaces: MgO(100)/Ag(100). Phys. Rev. B 61, 16948–16955 (2000)

7. Potthoff, M. & Nolting, W. Metallic surface of a Mott insulator? Mott insulating surface of a metal. Phys. Rev. B 60, 7834–7849 (1999)

8. Fang, Z., Solovyev, I. V. & Terakura, K. Phase diagram of tetragonal manganites. Phys. Rev. Lett. 84, 3169–3172 (2000)

9. Maiti, K., Mahadevan, P. & Sarma, D. D. Evolution of spectral function in a doped Mott insulator: Surface vs bulk contributions. Phys. Rev. Lett. 80, 2885–2888 (1998)

10. Matzdorf, R. et al. Ferromagnetism stabilized by lattice distortion at the surface of the p-wave superconductor Sr2RuO4 . Science 289, 746–748 (2000)

11. Moore, R. G. et al. Surface dynamics of the layered ruthenate Ca1.9Sr0.1RuO4 . Phys. Status Solidi (in the press)

12. Maiti, K. et al. Electronic structure of Ca1–xSrxVO3: A tale of two energy scales. Europhys. Lett. 55, 246–252 (2001)

13. Izumi, M. et al. Perovskite superlattices as tailored materials of correlated electrons. Mater. Sci. Eng. B 84, 53–57 (2001)

14. Ohtomo, A., Muller, D. A., Grazul, J. L. & Hwang, H. Y. Artificial charge–modulation in atomic-scale perovslite titanate superlattices. Nature 419, 378–380 (2002)

15. Sakudo, T. & Unoki, H. Dielectric properties of SrTiO3 at low temperatures. Phys. Rev. Lett. 26, 851–853 (1971)

16. Müller, K. A. & Burkard, H. SrTiO3: an intrinsic quantum paraelectric below 4K. Phys. Rev. B 19, 3593–3602 (1979)

17. Fujitani, H. & Asano, S. Full-potential band calculations on YTiO3 with a distorted perovskite structure. Phys. Rev. B 51, 2098–2102 (1995)

18. Mizokawa, T. & Fujimori, A. Unrestricted Hartree-Fock study of transition-metal oxides: Spin and orbital ordering in perovskite-type lattice. Phys. Rev. B 51, 12880–12883 (1995)

19. Okimoto, Y., Katsufuji, T., Okada, Y., Arima, T. & Tokura, Y. Optical spectra in (La, Y)TiO3: Variation of Mott-Hubbard gap features with change of electron correlation and band filling. Phys. Rev. B 51, 9581–9588 (1995)

20. Kiyama, T. & Itoh, M. Presence of 3d quadrupole moment in LaTiO3 studied by 47,49Ti NMR. Phys. Rev. Lett. 91, 167202 (2003)

21. Mochizuki, M. & Imada, M. Orbital-spin structure and lattice coupling in RTiO3 where R = La, Pr, Nd, and Sm. Phys. Rev. Lett. 91, 167203 (2003)

## Acknowledgements

We thank M. Potthoff, G. Sawatzky, W. Ku, H. Y. Hwang, E. W. Plummer and D. R. Hamann for conversations and the US NSF and the JSPS for support.

## Author information

Authors

### Corresponding author

Correspondence to Andrew J. Millis.

## Ethics declarations

### Competing interests

The authors declare that they have no competing financial interests.

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Okamoto, S., Millis, A. Electronic reconstruction at an interface between a Mott insulator and a band insulator. Nature 428, 630–633 (2004). https://doi.org/10.1038/nature02450

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• DOI: https://doi.org/10.1038/nature02450

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