Charge and orbital order at head-to-head domain walls in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">PbTiO</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>

Rahmanizadeh, K.; Wortmann, Daniel; Bihlmayer, Gustav; Blügel, Stefan

doi:10.1103/physrevb.90.115104

Cited by 22 publications

(17 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This behavior is very similar to the one observed in charged domain walls in perovskites, e.g., Pb(Ti,Zr)O 3 , where the structural distortions around the longitudinal domain wall are limited to a few unit cells [213]. Also in this case DFT + U calculations have shown that correlation effects have the tendency to localize Ti d electrons ensuring a rather sharp domain wall [214]. At least when 3d transition metal states are involved in the formation of the conduction band, this localization seems to be a general trend in oxides.…”

Section: Dft Calculation and Atomic Simulationssupporting

confidence: 59%

Influence of Dislocations in Transition Metal Oxides on Selected Physical and Chemical Properties

et al. 2018

View full text Add to dashboard Cite

Studies on dislocations in prototypic binary and ternary oxides (here TiO 2 and SrTiO 3 ) using modern TEM and scanning probe microscopy (SPM) techniques, combined with classical etch pits methods, are reviewed. Our review focuses on the important role of dislocations in the insulator-to-metal transition and for redox processes, which can be preferentially induced along dislocations using chemical and electrical gradients. It is surprising that, independently of the growth techniques, the density of dislocations in the surface layers of both prototypical oxides is high (10 9 /cm 2 for epipolished surfaces and up to 10 12 /cm 2 for the rough surface). The TEM and locally-conducting atomic force microscopy (LCAFM) measurements show that the dislocations create a network with the character of a hierarchical tree. The distribution of the dislocations in the plane of the surface is, in principle, inhomogeneous, namely a strong tendency for the bundling and creation of arrays or bands in the crystallographic <100> and <110> directions can be observed. The analysis of the core of dislocations using scanning transmission electron microscopy (STEM) techniques (such as EDX with atomic resolution, electron-energy loss spectroscopy (EELS)) shows unequivocally that the core of dislocations possesses a different crystallographic structure, electronic structure and chemical composition relative to the matrix. Because the Burgers vector of dislocations is per se invariant, the network of dislocations (with additional d 1 electrons) causes an electrical short-circuit of the matrix. This behavior is confirmed by LCAFM measurements for the stoichiometric crystals, moreover a similar dominant role of dislocations in channeling of the current after thermal reduction of the crystals or during resistive switching can be observed. In our opinion, the easy transformation of the chemical composition of the surface layers of both model oxides should be associated with the high concentration of extended defects in this region. Another important insight for the analysis of the physical properties in real oxide crystals (matrix + dislocations) comes from the studies of the nucleation of dislocations via in situ STEM indentation, namely that the dislocations can be simply nucleated under mechanical stimulus and can be easily moved at room temperature.

show abstract

Section: Dft Calculation and Atomic Simulationssupporting

confidence: 59%

Influence of Dislocations in Transition Metal Oxides on Selected Physical and Chemical Properties

et al. 2018

View full text Add to dashboard Cite

show abstract

“…The gap level close to the valence band originates from occupied Fe d orbitals oriented along Fe-O bonds being pushed energetically upward, while the one at higher energy is from the Fe d orbitals that are directed away from Fe-O bonds and are occupied by the excess electron. The same electron trapping (small electron polaron) has been discussed in the case of charged domain walls in ErMnO 3 [18] and PbTiO 3 [19]. In the case of BiFeO 3 , we could have actually expected electron trapping instead of delocalized metallic behavior because the d states of Fe at the bottom of the conduction band are relatively isolated both in space and in energy.…”

supporting

confidence: 64%

Electron trapping by neutral pristine ferroelectric domain walls in BiFeO3

2018

View full text Add to dashboard Cite

First-principles calculations for pristine neutral ferroelectric domain walls in BiFeO 3 reveal that excess electrons are selectively trapped by the domain walls, while holes are only weakly attracted. Such trapped excess electrons may be responsible for the thermally activated electrical conductivity at domain walls observed in experiments. In the case of a periodic array of domain walls, the trapped excess electrons create a zigzag potential, whose amplitude depends on the electron concentration in the material and the domain-wall distance. The potential is asymmetric for 71°and 109°domain walls. This could modify the open-circuit voltage in a solar cell and hence influence the photoelectric effect in BiFeO 3 .

show abstract

“…Due to the discrete electronic states resulting from the electric gas, signatures of resonant tunneling were observed, giving rise to quantum oscillations of the tunneling conductance. On the theoretical side, it has been shown that a head-to-head domain-wall structure can be created in a ferroelectric PbTiO 3 layer through the artificial electron doping at the interface [48], and such a domain wall can lead to spindependent resonant tunneling in a MFTJ [49]. These results demonstrate that a ferroelectric domain wall can be used as the controlling element of the transport properties of a FTJ [50].…”

Section: Introductionmentioning

confidence: 92%

Resonant tunneling across a ferroelectric domain wall

Tao

Velev

et al. 2018

Phys. Rev. B

View full text Add to dashboard Cite

Li, M.; Tao, L. L.; Velev, J. P.; and Tsymbal, Evgeny Y., "Resonant tunneling across a ferroelectric domain wall" (2018 Motivated by recent experimental observations, we explore electron transport properties of a ferroelectric tunnel junction (FTJ) with an embedded head-to-head ferroelectric domain wall, using first-principles density-functional theory calculations. We consider a FTJ with La 0.5 Sr 0.5 MnO 3 electrodes separated by a BaTiO 3 barrier layer and show that an in-plane charged domain wall in the ferroelectric BaTiO 3 can be induced by polar interfaces. The resulting V-shaped electrostatic potential profile across the BaTiO 3 layer creates a quantum well and leads to the formation of a two-dimensional electron gas, which stabilizes the domain wall. The confined electronic states in the barrier are responsible for resonant tunneling as is evident from our quantum-transport calculations. We find that the resonant tunneling is an orbital selective process, which leads to sharp spikes in the momentum-and energy-resolved transmission spectra. Our results indicate that domain walls embedded in FTJs can be used to control the electron transport.

show abstract

Charge and orbital order at head-to-head domain walls inPbTiO3

Cited by 22 publications

References 28 publications

Influence of Dislocations in Transition Metal Oxides on Selected Physical and Chemical Properties

Influence of Dislocations in Transition Metal Oxides on Selected Physical and Chemical Properties

Electron trapping by neutral pristine ferroelectric domain walls in BiFeO3

Resonant tunneling across a ferroelectric domain wall

Contact Info

Product

Resources

About