Condensation of two-dimensional oxide-interfacial charges into one-dimensional electron chains by the misfit-dislocation strain field

Abstract

The success of semiconductor technology is largely ascribed to controlled impacts of strains and defects on the two-dimensional interfacial charges. Interfacial charges also appear in oxide heterojunctions such as LaAlO 3 /SrTiO 3 and (Nd 0.35 Sr 0.65 )MnO 3 /SrTiO 3 . How the localized strain field of one-dimensional misfit dislocations, defects resulting from the intrinsic misfit strains, would affect the extended oxide-interfacial charges is intriguing and remains unresolved. Here we show the atomic-scale observation of one-dimensional electron chains formed in (Nd 0.35 Sr 0.65 )MnO 3 /SrTiO 3 by the condensation of characteristic twodimensional interfacial charges into the strain field of periodically arrayed misfit dislocations, using chemical mapping and quantification by scanning transmission electron microscopy. The strain-relaxed inter-dislocation regions are readily charge depleted, otherwise decorated by the pristine charges, and the corresponding total-energy calculations unravel the undocumented charge-reservoir role played by the dislocation-strain field. This two-dimensionalto-one-dimensional electronic condensation represents a novel electronic-inhomogeneity mechanism at oxide interfaces and could stimulate further studies of one-dimensional electron density in oxide heterostructures.

Electronic Structure and Infrared Light Emission in Dislocation-Engineered Silicon

“…This result suggested that the dislocation array could have influence on the electronic defect level distribution in the bandgap. Recently, the condensation of two-dimensional oxide-interfacial charges into one-dimensional electron chains by the misfit-dislocation strain field was reported [18]. Our STM image has responded their results that the dislocation line can be revealed by the scanning tunneling current with higher charge density condensed on the dislocation array.…”

Edge dislocation slows down oxide ion diffusion in doped CeO2 by segregation of charged defects

“…The lattice mismatch can be accommodated as elastic strain or as a combination of elastic and plastic strain. A high density of dislocations (two orders higher than those in bulk) can be found at the interface of thin films [6][7][8] upon relaxation of elastic strain. This high density of dislocations makes the study of their effect on the properties of the material of paramount importance.…”

Atomic mapping of Ruddlesden-Popper faults in transparent conducting BaSnO3-based thin films

“…Generally, in contrast with the bulk, thin films are not only the existing status for many materials in devices, but they also promise many novel properties due to the unique structural features1112131415. For example, misfit dislocations (MDs) are commonly observed in thin films while one dimensional electron chains are found at these MDs in magnetic thin films11.…”

“…For example, misfit dislocations (MDs) are commonly observed in thin films while one dimensional electron chains are found at these MDs in magnetic thin films11. And interfaces, such as film/substrate interfaces, twins or stacking faults, can provide another degree of freedom to mediate the property of thin films, where superconductivity13, ferroelectricity14, and novel magnetic phase15 can be generated.…”