Electron energy‐loss near‐edge structure – a tool for the investigation of electronic structure on the nanometre scale

Keast, V. J.; Scott, A. J.; Brydson, Rik; Williams, David B.; Bruley, J.

doi:10.1046/j.1365-2818.2001.00898.x

Cited by 179 publications

(122 citation statements)

References 166 publications

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“…Within the dipole approximation, when the X-ray momentum vector and X-ray polarization vectors are equal, the EEL spectrum is directly equivalent to the X-ray absorption cross-section (see ref. 38). The core and valence electrons were treated with ultrasoft pseudopotentials 39 and the PBEsol exchange-correlation functional 40 .…”

Section: Resultsmentioning

confidence: 99%

Polarization screening-induced magnetic phase gradients at complex oxide interfaces

et al. 2015

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Thin-film oxide heterostructures show great potential for use in spintronic memories, where electronic charge and spin are coupled to transport information. Here we use a La 0.7 Sr 0.3 MnO 3 (LSMO)/PbZr 0.2 Ti 0.8 O 3 (PZT) model system to explore how local variations in electronic and magnetic phases mediate this coupling. We present direct, local measurements of valence, ferroelectric polarization and magnetization, from which we map the phases at the LSMO/PZT interface. We combine these experimental results with electronic structure calculations to elucidate the microscopic interactions governing the interfacial response of this system. We observe a magnetic asymmetry at the LSMO/PZT interface that depends on the local PZT polarization and gives rise to gradients in local magnetic moments; this is associated with a metal-insulator transition at the interface, which results in significantly different charge-transfer screening lengths. This study establishes a framework to understand the fundamental asymmetries of magnetoelectric coupling in oxide heterostructures.

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Section: Resultsmentioning

confidence: 99%

Polarization screening-induced magnetic phase gradients at complex oxide interfaces

et al. 2015

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“…Electron energy-loss experiments probe the part of the molecular orbital which is projected onto the atom with the original 2p state. Although one may not be able to distinguish between the effects of covalent or ionic bonding, 22 important information on bonding, charge compensation, and hybridization upon compound formation can still be revealed. 16,23,24 The cobalt-based skutterudites are among those which have received most attention in studies of skutterudites as thermoelectric materials.…”

Section: Introductionmentioning

confidence: 99%

Transition metald-band occupancy in skutterudites studied by electron energy-loss spectroscopy

et al. 2007

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The transition-metal 3d occupancy of a series of thermoelectric skutterudites is investigated using electron energy-loss spectroscopy. We find that bonding causes an emptying of the 3d states in the binary skutterudites CoP 3 , CoAs 3 , CoSb 3 , and NiP 3 , while compared to the pure Fe the 3d occupancy in LaFe 4 P 12 is significantly increased, consistent with the idea that each interstitial La atom ͑rattler͒ donates three electrons to compensate for missing valence electron of Fe as compared to Co. These experimental results are in agreement with previous models suggesting a predominantly covalent bonding between transition metal and pnictogen atoms in skutterudites, and provide evidence of charge transfer from La to the Fe-P complex in LaFe 4 P 12 .

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“…Furthermore, the near-edge fine-structure of EELS edges (ELNES) reflects the local unoccupied density of states 5 at the exited atom [15,16], thus additional information on phases, bonding and electronic structure can be obtained in parallel. Using the combination of STEM and EELS, it is possible to measure the composition and obtain electronic structure information with a spatial resolution approaching atomic dimensions [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Characterization of advanced gate stacks for Si CMOS by electron energy-loss spectroscopy in scanning transmission electron microscopy

Foran¹,

Barnett²,

Lysaght³

et al. 2005

Journal of Electron Spectroscopy and Related Phenomena

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Novel metal oxide films and new metal gates are currently being developed for future generations of Si based field-effect transistors as the SiO 2 gate dielectric and polycrystalline Si gate electrode are reaching scaling limits. These new gate stacks are often comprised of subnanometer layers. Device properties are increasingly controlled by the complex structure and chemistry of interfaces between the layers. Electron energy loss spectroscopy (EELS) in scanning transmission electron microscopy (STEM) is capable of providing insights into interfacial chemistry and local atomic structure with a spatial resolution unmatched by any other technique. Using gate stacks with Hf-silicate dielectrics as examples, we demonstrate the capabilities of STEM/EELS for analyzing the interfacial chemistry of novel gate stacks. We show that a-priori unknown reaction layers of a few Å thickness can be detected and identified even in the presence of substantial interfacial roughness that may obscure such layers in a highresolution image. We discuss some experimental aspects of STEM/EELS chemical profiling applied to gate stacks and the factors affecting the interpretation. In particular, the effects of interfacial roughness, beam spreading, elemental analysis in a heavily scattering matrix, and the interpretation of the EELS core-loss fine-structures from ultrathin layers are discussed.

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Electron energy‐loss near‐edge structure – a tool for the investigation of electronic structure on the nanometre scale

Cited by 179 publications

References 166 publications

Polarization screening-induced magnetic phase gradients at complex oxide interfaces

Polarization screening-induced magnetic phase gradients at complex oxide interfaces

Transition metald-band occupancy in skutterudites studied by electron energy-loss spectroscopy

Characterization of advanced gate stacks for Si CMOS by electron energy-loss spectroscopy in scanning transmission electron microscopy

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