Ab initio investigation of electronic and magnetic properties of antiferromagnetic/ferroelectric LaMnO₃/BaTiO₃ interface

Abstract

We investigate the structural, electronic and magnetic properties of LaMnO 3 /BaTiO 3 heterostructure by means of ab initio calculations within the GGA+U approach. We consider the heterostructure when ferroelectric polarization in the BaTiO 3 film is oriented perpendicular to the LaMnO 3 substrate. We present atom and spin-resolved density of states calculations for LaMnO 3 /BaTiO 3 heterostructure with different number of BaTiO 3 overlayers as well as layer-resolved spectra for the conducting heterostructure. We found that the LaMnO 3 /BaTiO 3 heterostructure becomes conducting with a significant spin polarization indicating that the interface becomes ferromagnetically ordered. The propose concept of a ferroelectrically controlled interface ferromagnetism that offers the possibility to design novel electronic devices.

Origin of Negative Photoconductivity at the Interface of Ba0.8Sr0.2TiO3/LaMnO3/Ba0.8Sr0.2TiO3 Heterostructures

“…If the occurrence of a highly conductive region at the interface depends on the polarization of the ferroelectric oxide part, switching the direction of this polarization would allow for commanding the conductive properties of the material. Previously, the transition to the state with 2DEG at the interface, which is connected to a sharp change in the perpendicular component of the polarization at the interface, was demonstrated [ 22 , 23 , 24 ], and we detected the presence of a highly conductive state at the interface of a heterostructure based on a ferroelectric and a dielectric, Ba 0.8 Sr 0.2 TiO 3 /LaMnO 3 [ 22 ]. While optical, photoconductive, and other properties of rare earth oxides are well known [ 1 , 2 , 3 , 4 ], the optical and especially the photoconductive properties of the 2DEG on the interfaces of two insulating materials are not reported.…”

DFT Insight into Conductive and Magnetic Properties of Heterostructures with BaTiO3 Overlayer

“…At the first stage bulk structures of silicon, barium titanate in the tetragonal phase and lanthanum manganite with an A type of ferromagnetic ordering (A-AFM) were examined by means of DFT. The explanation for the choice of the phases and magnetic ordering was presented in our previous research [ 43 ]. Here, we emphasize that all compounds are semiconductors with indirect band gaps of 0.615 eV, 2.113 eV and 1 eV for Si, BTO and LaMnO 3 , respectively (the unit cells along with the density of states spectra are shown in Figure 1 ).…”

“…The electrical and magnetic properties have been studied for heterostructures formed by antiferromagnetic LaMnO 3 single crystals with epitaxial films of ferroelectric Ba 0.8 Sr 0.2 TiO 3 (BSTO) were deposited on top of them by reactive sputtering of stoichiometric targets, using the RF-sputtering method [ 42 , 43 ] at 650 °C. The average roughness of the LaMnO 3 single crystals surface was approximately 1 nm before deposition.…”

Advantages of Ferroelectrics as a Component of Heterostructures for Electronic Purposes: A DFT Insight

“…Such polarisation, for instance in LaAlO 3 /SrTiO 3 , arises due to the charge sequence in LaAlO 3 atomic layers. However, 2DEG can occur even without charged atomic layers thanks to the presence of spontaneous polarisation in ferroelectric thin films [1][2][3][4][5][6]. This means that the electronic properties of the arising state can be tuned by an external field by changing the direction of the ferroelectric dipoles.…”