Properties of Dipole-Mode Vibrational Energy Losses Recorded From a TEM Specimen

Egerton, R.F.; Venkatraman, Kartik; March, Katia; Crozier, Peter A.

doi:10.1017/s1431927620024423

Cited by 7 publications

(3 citation statements)

References 55 publications

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“…The profile of the signal between 170 and 190 meV does not follow the HAADF signal profile; it is approximately constant with decreasing nanoparticle thickness up to ~10 nm from the edge. This implies that it is more of a surface signal (Egerton et al, 2020). It then falls rapidly till the probe is ~3 nm from the edge, and then drops more slowly to ~30% of its maximum value at the exact edge position.…”

Section: Resultsmentioning

confidence: 99%

Role of Convergence and Collection Angles in the Excitation of Long- and Short-Wavelength Phonons with Vibrational Electron Energy-Loss Spectroscopy

Venkatraman

Crozier

2021

Microsc Microanal

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Section: Resultsmentioning

confidence: 99%

Role of Convergence and Collection Angles in the Excitation of Long- and Short-Wavelength Phonons with Vibrational Electron Energy-Loss Spectroscopy

Venkatraman

Crozier

2021

Microsc Microanal

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“…In contrast to dipole scattering that involves small momentum transfer (q ∼ 0), impact scattering involves large momentum transfer and has broad angular distribution (large scattering angles). 156,160,161 The long-ranged electron-dipole interactions are the major limiting factor when it comes to the attainable spatial resolution in vibrational STEM-EELS. 65,162,163 Due to the large delocalization distance of dipole modes, the spatial resolution in early vibrational EELS demonstrations was limited to several tens of nm and the vibrational signature of the sample was primarily detected using aloof configurations outside the sample (tens of nm away from the edge).…”

Section: Experimental Considerations For Achieving Atomic Resolution ...mentioning

confidence: 99%

“…The scattering cross-section in impact scattering is significantly smaller than the one for long-range dipole scattering. In contrast to dipole scattering that involves small momentum transfer ( q ∼ 0), impact scattering involves large momentum transfer and has broad angular distribution (large scattering angles). ,, …”

Section: Probing Collective Excitations In Quantum Materials Using Co...mentioning

confidence: 99%

Accelerating Quantum Materials Development with Advances in Transmission Electron Microscopy

Moradifar,

Liu,

Shi

et al. 2023

Chem. Rev.

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Quantum materials are driving a technology revolution in sensing, communication, and computing, while simultaneously testing many core theories of the past century. Materials such as topological insulators, complex oxides, superconductors, quantum dots, color center-hosting semiconductors, and other types of strongly correlated materials can exhibit exotic properties such as edge conductivity, multiferroicity, magnetoresistance, superconductivity, single photon emission, and optical-spin locking. These emergent properties arise and depend strongly on the material’s detailed atomic-scale structure, including atomic defects, dopants, and lattice stacking. In this review, we describe how progress in the field of electron microscopy (EM), including in situ and in operando EM, can accelerate advances in quantum materials and quantum excitations. We begin by describing fundamental EM principles and operation modes. We then discuss various EM methods such as (i) EM spectroscopies, including electron energy loss spectroscopy (EELS), cathodoluminescence (CL), and electron energy gain spectroscopy (EEGS); (ii) four-dimensional scanning transmission electron microscopy (4D-STEM); (iii) dynamic and ultrafast EM (UEM); (iv) complementary ultrafast spectroscopies (UED, XFEL); and (v) atomic electron tomography (AET). We describe how these methods could inform structure–function relations in quantum materials down to the picometer scale and femtosecond time resolution, and how they enable precision positioning of atomic defects and high-resolution manipulation of quantum materials. For each method, we also describe existing limitations to solve open quantum mechanical questions, and how they might be addressed to accelerate progress. Among numerous notable results, our review highlights how EM is enabling identification of the 3D structure of quantum defects; measuring reversible and metastable dynamics of quantum excitations; mapping exciton states and single photon emission; measuring nanoscale thermal transport and coupled excitation dynamics; and measuring the internal electric field and charge density distribution of quantum heterointerfaces- all at the quantum materials’ intrinsic atomic and near atomic-length scale. We conclude by describing open challenges for the future, including achieving stable sample holders for ultralow temperature (below 10K) atomic-scale spatial resolution, stable spectrometers that enable meV energy resolution, and high-resolution, dynamic mapping of magnetic and spin fields. With atomic manipulation and ultrafast characterization enabled by EM, quantum materials will be poised to integrate into many of the sustainable and energy-efficient technologies needed for the 21st century.

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Nanoscale Vibrational Spectroscopy in a Scanning Transmission Electron Microscope

Venkatraman¹,

Chi²

2023

Encyclopedia of Nanomaterials

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Properties of Dipole-Mode Vibrational Energy Losses Recorded From a TEM Specimen

Abstract: Abstract

Cited by 7 publications

References 55 publications

Role of Convergence and Collection Angles in the Excitation of Long- and Short-Wavelength Phonons with Vibrational Electron Energy-Loss Spectroscopy

Role of Convergence and Collection Angles in the Excitation of Long- and Short-Wavelength Phonons with Vibrational Electron Energy-Loss Spectroscopy

Accelerating Quantum Materials Development with Advances in Transmission Electron Microscopy

Nanoscale Vibrational Spectroscopy in a Scanning Transmission Electron Microscope

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