中国物理B ›› 2008, Vol. 17 ›› Issue (11): 4305-4311.doi: 10.1088/1674-1056/17/11/057

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Interface dipole induced by asymmetric exchange effect in Mott-insulator/Mott-insulator heterojunction

汪 军1, 郝 雷2   

  1. (1)Department of Physics, Southeast University, Nanjing 210096, China; (2)National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
  • 收稿日期:2008-06-16 修回日期:2008-06-25 出版日期:2008-11-20 发布日期:2008-11-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10574021, 90403011, and 10704016).

Interface dipole induced by asymmetric exchange effect in Mott-insulator/Mott-insulator heterojunction

Hao Lei (郝雷)a,  Wang Jun(汪军)b   

  1. a National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China; b Department of Physics, Southeast University, Nanjing 210096, China
  • Received:2008-06-16 Revised:2008-06-25 Online:2008-11-20 Published:2008-11-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10574021, 90403011, and 10704016).

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摘要： We study theoretically the interfacial electronic property of a heterojunction made from two Mott insulators (MI) with different magnetic structures. By means of unrestricted Hartree-Fock calculations in real space, we find that a charge dipole can form spontaneously near the interface of the MI/MI heterojunction. The magnitude of this charge dipole depends strongly on the magnetic states of both sides of the heterojunction. Combining with the result from an exactly solvable two-site toy model, we argue that the interface dipole arises from exchange effects as well as its asymmetry intrinsic to the heterojunction near the interface. Our study may shed light on the fabrication of ultrathin ferroelectric and magnetoelectric devices.

关键词: Mott insulator heterojunction, interface dipole, asymmetric exchange

Abstract: We study theoretically the interfacial electronic property of a heterojunction made from two Mott insulators (MI) with different magnetic structures. By means of unrestricted Hartree-Fock calculations in real space, we find that a charge dipole can form spontaneously near the interface of the MI/MI heterojunction. The magnitude of this charge dipole depends strongly on the magnetic states of both sides of the heterojunction. Combining with the result from an exactly solvable two-site toy model, we argue that the interface dipole arises from exchange effects as well as its asymmetry intrinsic to the heterojunction near the interface. Our study may shed light on the fabrication of ultrathin ferroelectric and magnetoelectric devices.

Key words: Mott insulator heterojunction, interface dipole, asymmetric exchange

中图分类号:  (Surface states, band structure, electron density of states)

  • 73.20.At
71.15.Ap (Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.)) 75.30.Et (Exchange and superexchange interactions) 75.70.Cn (Magnetic properties of interfaces (multilayers, superlattices, heterostructures))