Twist-induced interlayer charge buildup in a WS2 bilayer revealed by electron Compton scattering and density functional theory (2023)
Journal Article
Talmantaite, A., Xie, Y., Cohen, A., Mohapatra, P., Ismach, A., Mizoguchi, T., …Mendis, B. (2023). Twist-induced interlayer charge buildup in a WS2 bilayer revealed by electron Compton scattering and density functional theory. Physical Review B, 107(23), Article 235424. https://doi.org/10.1103/physrevb.107.235424

Exotic properties emerge from the electronic structure of few-layer transition-metal dichalcogenides (TMDs), such as direct band gaps in monolayers and moiré excitons in twisted bilayers, which are exploited in modern optoelectronic devices and twist... Read More about Twist-induced interlayer charge buildup in a WS2 bilayer revealed by electron Compton scattering and density functional theory.

A “Phase Scrambling” Algorithm for Parallel Multislice Simulation of Multiple Phonon and Plasmon Scattering Configurations (2023)
Journal Article
Mendis, B. G. (2023). A “Phase Scrambling” Algorithm for Parallel Multislice Simulation of Multiple Phonon and Plasmon Scattering Configurations. Microscopy and Microanalysis, 29(3), 1111-1123. https://doi.org/10.1093/micmic/ozad052

Multislice simulations of 4D scanning transmission electron microscopy (4D STEM) data are computationally demanding due to the large number of STEM probe positions that must be calculated. For accurate analysis, inelastic scattering from phonons and... Read More about A “Phase Scrambling” Algorithm for Parallel Multislice Simulation of Multiple Phonon and Plasmon Scattering Configurations.

Coherent electron Compton scattering and the non-diagonal electron momentum density of solids (2022)
Journal Article
Mendis, B. (2023). Coherent electron Compton scattering and the non-diagonal electron momentum density of solids. Ultramicroscopy, 245, https://doi.org/10.1016/j.ultramic.2022.113664

Experimental techniques that probe the electronic structure of crystalline solids are vital for exploring novel condensed matter phenomena. In coherent Compton scattering the Compton signal due to interference of an incident and Bragg diffracted beam... Read More about Coherent electron Compton scattering and the non-diagonal electron momentum density of solids.

Structure and electronic properties of domain walls and stacking fault defects in prospective photoferroic materials bournonite and enargite (2022)
Journal Article
Rigby, O., Richards-Hlabangana, T., Ramasse, Q., MacLaren, I., Lomas-Zapata, R., Rumsey, M., …Mendis, B. (2022). Structure and electronic properties of domain walls and stacking fault defects in prospective photoferroic materials bournonite and enargite. Journal of Applied Physics, 132(18), Article 185001. https://doi.org/10.1063/5.0095091

Bournonite (CuPbSbS3) and enargite (Cu3AsS4) have recently been used as absorber layers in thin-film photovoltaic devices due to their ideal bandgap and ferroelectric properties. An understanding of the ferroelectric domain structure in these materia... Read More about Structure and electronic properties of domain walls and stacking fault defects in prospective photoferroic materials bournonite and enargite.

Background subtraction in electron Compton spectroscopy (2022)
Journal Article
Mendis, B. (2022). Background subtraction in electron Compton spectroscopy. Micron, 163, Article 103363. https://doi.org/10.1016/j.micron.2022.103363

Compton scattering in electron energy loss spectroscopy (EELS) is used to quantify the momentum distribution of occupied electronic states in a solid. The Compton signal is a broad feature with a width of several hundred eV. Furthermore, the weak int... Read More about Background subtraction in electron Compton spectroscopy.

Towards Electron Energy Loss Compton Spectra Free From Dynamical Diffraction Artifacts (2022)
Journal Article
Mendis, B. G., & Talmantaite, A. (2022). Towards Electron Energy Loss Compton Spectra Free From Dynamical Diffraction Artifacts. Microscopy and Microanalysis, https://doi.org/10.1017/s1431927622012223

The Compton signal in electron energy loss spectroscopy (EELS) is used to determine the projected electron momentum density of states for the solid. A frequent limitation however is the strong dynamical scattering of the incident electron beam within... Read More about Towards Electron Energy Loss Compton Spectra Free From Dynamical Diffraction Artifacts.

Quantum theory of magnon excitation by high energy electron beams (2022)
Journal Article
Mendis, B. (2022). Quantum theory of magnon excitation by high energy electron beams. Ultramicroscopy, 239, Article 113548. https://doi.org/10.1016/j.ultramic.2022.113548

The role of magnon inelastic scattering in high energy electron diffraction of spin unpolarised electron beams, including vortex beams, is investigated theoretically for a Heisenberg ferromagnet. The interaction is between the atomic magnetic dipoles... Read More about Quantum theory of magnon excitation by high energy electron beams.

Selenium passivates grain boundaries in alloyed CdTe solar cells (2022)
Journal Article
Fiducia, T., Howkins, A., Abbas, A., Mendis, B., Munshi, A., Barth, K., …Walls, J. (2022). Selenium passivates grain boundaries in alloyed CdTe solar cells. Solar Energy Materials and Solar Cells, 238, Article 111595. https://doi.org/10.1016/j.solmat.2022.111595

Cadmium telluride (CdTe) solar cells have achieved efficiencies of over 22%, despite having absorber layer grain sizes less than 10 μm and hence a very high density of grain boundaries. Recent research has shown that this is possible because of parti... Read More about Selenium passivates grain boundaries in alloyed CdTe solar cells.

Differing Impacts of Blended Fullerene Acceptors on the Performance of Ternary Organic Solar Cells (2021)
Journal Article
Palacios-Gómez, D. A., Huerta Flores, A. M., MacKenzie, R. C., Pearson, C., Alanazi, F., Mendis, B. G., & Groves, C. (2021). Differing Impacts of Blended Fullerene Acceptors on the Performance of Ternary Organic Solar Cells. ACS Applied Energy Materials, 4(10), 10867-10876. https://doi.org/10.1021/acsaem.1c01833

Organic photovoltaic (OPV) devices offer the ability to tune the electronic and optical properties of the active layer by selection of a wide range of molecules; however, their power conversion efficiencies currently lag other competing photovoltaic... Read More about Differing Impacts of Blended Fullerene Acceptors on the Performance of Ternary Organic Solar Cells.

A semi-classical theory of magnetic inelastic scattering in transmission electron energy loss spectroscopy (2021)
Journal Article
Mendis, B. (2021). A semi-classical theory of magnetic inelastic scattering in transmission electron energy loss spectroscopy. Ultramicroscopy, 230, Article 113390. https://doi.org/10.1016/j.ultramic.2021.113390

The feasibility of detecting magnetic excitations using monochromated electron energy loss spectroscopy in the transmission electron microscope is examined. Inelastic scattering cross-sections are derived using a semi-classical electrodynamic model,... Read More about A semi-classical theory of magnetic inelastic scattering in transmission electron energy loss spectroscopy.

Surface Core Hole Electron Energy-Loss Fine Structure in MgO: Experiment and Theory (2021)
Journal Article
Mendis, B. (2021). Surface Core Hole Electron Energy-Loss Fine Structure in MgO: Experiment and Theory. Microscopy and Microanalysis, 27(6), 1316-1327. https://doi.org/10.1017/s1431927621012691

Core holes are an important contributing factor to the core-loss fine structure in electron energy-loss spectroscopy (EELS). While there has been much work on bulk materials, less is known about core hole screening in more complex dielectric environm... Read More about Surface Core Hole Electron Energy-Loss Fine Structure in MgO: Experiment and Theory.

Removal of core hole distortion from ionization edges in electron energy loss spectroscopy (2021)
Journal Article
Mendis, B., & Ramasse, Q. (2021). Removal of core hole distortion from ionization edges in electron energy loss spectroscopy. Physical Review B, 103(20), Article 205102. https://doi.org/10.1103/physrevb.103.205102

The near-edge fine structure in electron energy loss spectra is used to probe the electronic bonding environment of materials at high spatial resolution. Often, however, deviations from the ground state electronic properties are observed, due to the... Read More about Removal of core hole distortion from ionization edges in electron energy loss spectroscopy.

Inelastic Scattering in Electron Backscatter Diffraction and Electron Channeling Contrast Imaging (2020)
Journal Article
Mendis, B. G., Barthel, J., Findlay, S. D., & Allen, L. J. (2020). Inelastic Scattering in Electron Backscatter Diffraction and Electron Channeling Contrast Imaging. Microscopy and Microanalysis, 26(6), 1147-1157. https://doi.org/10.1017/s1431927620024605

Electron backscatter diffraction (EBSD) and electron channeling contrast imaging (ECCI) are used to extract crystallographic information from bulk samples, such as their crystal structure and orientation as well as the presence of any dislocation and... Read More about Inelastic Scattering in Electron Backscatter Diffraction and Electron Channeling Contrast Imaging.

Microscopic Analysis of Interdiffusion and Void Formation in CdTe(1–x)Sex and CdTe Layers (2020)
Journal Article
Baines, T., Bowen, L., Mendis, B. G., & Major, J. D. (2020). Microscopic Analysis of Interdiffusion and Void Formation in CdTe(1–x)Sex and CdTe Layers. ACS Applied Materials and Interfaces, 12(34), 38070-38075. https://doi.org/10.1021/acsami.0c09381

The use of CdSe layers has recently emerged as a route to improving CdTe photovoltaics through the formation of a CdTe(1–x)Sex (CST) phase. However, the extent of the Se diffusion and the influence it has on the CdTe grain structure has not been wide... Read More about Microscopic Analysis of Interdiffusion and Void Formation in CdTe(1–x)Sex and CdTe Layers.

Theory underpinning multislice simulations with plasmon energy losses (2020)
Journal Article
Mendis, B. (2020). Theory underpinning multislice simulations with plasmon energy losses. Microscopy, 69(3), 173-175. https://doi.org/10.1093/jmicro/dfaa003

The theoretical conditions for small-angle inelastic scattering where the incident electron can effectively be treated as a particle moving in a uniform potential is examined. The motivation for this work is the recent development of a multislice met... Read More about Theory underpinning multislice simulations with plasmon energy losses.

Angular dependence of fast-electron scattering from materials (2020)
Journal Article
Barthel, J., Cattaneo, M., Mendis, B. G., Findlay, S. D., & Allen, L. J. (2020). Angular dependence of fast-electron scattering from materials. Physical Review B, 101(18), Article 184109. https://doi.org/10.1103/physrevb.101.184109

Angular resolved scanning transmission electron microscopy is an important tool for investigating the properties of materials. However, several recent studies have observed appreciable discrepancies in the angular scattering distribution between expe... Read More about Angular dependence of fast-electron scattering from materials.

Evidence for Self-healing Benign Grain Boundaries and a Highly Defective Sb2Se3–CdS Interfacial Layer in Sb2Se3 Thin-Film Photovoltaics (2020)
Journal Article
Williams, R. E., Ramasse, Q. M., McKenna, K. P., Phillips, L. J., Yates, P. J., Hutter, O. S., …Mendis, B. G. (2020). Evidence for Self-healing Benign Grain Boundaries and a Highly Defective Sb2Se3–CdS Interfacial Layer in Sb2Se3 Thin-Film Photovoltaics. ACS Applied Materials and Interfaces, 12(19), 21730-21738. https://doi.org/10.1021/acsami.0c03690

The crystal structure of Sb2Se3 gives rise to unique properties that cannot otherwise be achieved with conventional thin-film photovoltaic materials, such as CdTe or Cu(In,Ga)Se2. It has previously been proposed that grain boundaries can be made beni... Read More about Evidence for Self-healing Benign Grain Boundaries and a Highly Defective Sb2Se3–CdS Interfacial Layer in Sb2Se3 Thin-Film Photovoltaics.

Electron Compton scattering and the measurement of electron momentum distributions in solids (2020)
Journal Article
Talmantaite, A., Hunt, M., & Mendis, B. (2020). Electron Compton scattering and the measurement of electron momentum distributions in solids. Journal of Microscopy, 279(3), 185-188. https://doi.org/10.1111/jmi.12854

Electron Compton scattering is a technique that gives information on the electron momentum density of states and is used to characterize the ground state electronic structure in solids. Extracting the momentum density of states requires us to assume... Read More about Electron Compton scattering and the measurement of electron momentum distributions in solids.

An inelastic multislice simulation method incorporating plasmon energy losses (2019)
Journal Article
Mendis, B. (2019). An inelastic multislice simulation method incorporating plasmon energy losses. Ultramicroscopy, 206, Article 112816. https://doi.org/10.1016/j.ultramic.2019.112816

Quantitative electron microscopy requires accurate simulation methods that take into account both elastic and inelastic scattering of the high energy electrons within the specimen. Here a method to combine plasmon excitations, the dominant energy los... Read More about An inelastic multislice simulation method incorporating plasmon energy losses.

Planck's generalised radiation law and its implications for cathodoluminescence spectra (2019)
Journal Article
Mendis, B. (2019). Planck's generalised radiation law and its implications for cathodoluminescence spectra. Ultramicroscopy, 204, 73-80. https://doi.org/10.1016/j.ultramic.2019.05.007

Cathodoluminescence (CL) is an important analytical technique for probing the optical properties of materials at high spatial resolution. Interpretation of CL spectra is however complicated by the fact that the spectrum depends on the carrier injecti... Read More about Planck's generalised radiation law and its implications for cathodoluminescence spectra.