Two-Dimensional Mapping of Chemical Information at Atomic Resolution

Abstract

The simultaneous measurement of structural and chemical information at the atomic scale provides fundamental insights into the connection between form and function in materials science and nanotechnology. We demonstrate structural and chemical mapping in Bi(0.5) Sr(0.5) MnO3 using an aberration-corrected scanning transmission electron microscope. Two-dimensional mapping is made possible by an adapted method for fast acquisition of electron energy-loss spectra. The experimental data are supported by simulations, which help to explain the less intuitive features.

Towards artifact-free atomic-resolution elemental mapping with electron energy-loss spectroscopy

“…However, it has also been revealed that extra caution is required to properly interpret the contrast of maps acquired at the atomic scale. 2,[12][13][14][18][19][20] In particular, a substantial component of undesirable "elastic contrast" can be preserved due to probe electrons being elastically scattered beyond the EELS collection angle. Such large-angle elastic scattering occurs especially in the presence of heavy-atom columns, and it is the basic mechanism to form an incoherent bright-field (IBF) image.…”

“…Over the last decade, atomic-resolution core-level spectroscopy has developed to become an extremely powerful tool for probing nanomaterials. [1][2][3][4][5][6][7][8] Performed in a scanning transmission electron microscope (STEM), the technique uses an atomic-sized electron probe to excite core-level electrons in the sample, while detectors monitor the spectra of energy-loss electrons and/or the flux of characteristic x-rays. A wealth of atomic-scale information is provided, 3,4,[9][10][11] including the locations and species of atoms, i.e., elemental maps, and, in the case of electron energy-loss spectroscopy (EELS), information on electronic bonding.…”

2D Atomic Mapping of Oxidation States in Transition Metal Oxides by Scanning Transmission Electron Microscopy and Electron Energy-Loss Spectroscopy

“…However, the exact mechanism of multiferroic behavior is not fully understood to date. A method allowing for direct mapping of cation valence states in these materials at atomic resolution should therefore provide further insight into the origin of multiferroicity.Recently, atomic resolution elemental mapping has become feasible by means of spatially resolved electron energy-loss spectroscopy and energy dispersive x-ray spectroscopy in a scanning transmission electron microscope (STEM-EELS and STEM-EDX) [4][5][6][7][8][9]. At the same time, tremendous effort is being invested into the identification of the oxidation states of cations using electron energy-loss spectroscopy (EELS).…”

Atomic scale real-space mapping of holes in YBa2Cu3O6+δ

“…Accordingly, a more complete description of the electronic structure of YBCO requires more direct means to distinguish the electronic structure of different sites. In this report, we make use of recent developments in EELS resolution [13][14][15][16] to measure O K and Cu L 2,3 spectra in YBa 2 Cu 3 O 6 þ d with sufficient spatial and energy resolution to clearly distinguish the role of the planes and chains in real space. We show atomically resolved elemental maps for both doped and undoped YBCO as well as fine structure differences between chains and planes at both the Cu L and the O K edges.…”