E02-JEM ARM 300CF
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Sam
Sullivan-Allsop
,
Nick
Clark
,
Wendong
Wang
,
Rongsheng
Cai
,
William
Thornley
,
David G.
Hopkinson
,
James G.
Mchugh
,
Ben
Davies
,
Samuel
Pattisson
,
Nicholas F.
Dummer
,
Rui
Zhang
,
Matthew
Lindley
,
Gareth
Tainton
,
Jack
Harrison
,
Hugo
De Latour
,
Joseph
Parker
,
Joshua
Swindell
,
Eli G.
Castanon
,
Amy
Carl
,
David J.
Lewis
,
Natalia
Martsinovich
,
Christopher S.
Allen
,
Mohsen
Danaie
,
Andrew J.
Logsdail
,
Vladimir
Fal’ko
,
Graham J.
Hutchings
,
Alex
Summerfield
,
Roman
Gorbachev
,
Sarah J.
Haigh
Diamond Proposal Number(s):
[33252, 35552]
Abstract: The structure and dynamics of adsorbed atoms (adatoms) at solid-liquid interfaces determine the performance of advanced catalysts, electrochemical devices, molecular separation technologies, and metal extraction from waste streams. However, in situ investigations of atomically dispersed metals in various chemical environments have been prevented by insufficient imaging resolution and solvent incompatibility. In this study, we combined a specimen design that provides atomic resolution in liquid-phase electron microscopy with deep learning–enabled analysis to explore the interactions between gold adatoms, graphite support, and the solvent collectively. We tracked the locations of >106 graphite-supported gold adatoms, dimers, and larger clusters in five solvents. Although their initial atomic dispersion was determined by the solvent polarity, fast drying kinetics at low temperature was required for optimizing catalytic performance.
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Apr 2026
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E02-JEM ARM 300CF
I05-ARPES
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Amy
Carl
,
Nicholas
Clark
,
David G.
Hopkinson
,
Matthew
Hamer
,
Matthew
Watson
,
Laxman
Nagireddy
,
James E.
Nunn
,
Alexei
Barinov
,
Yichao
Zou
,
William
Thornley
,
Casey
Cheung
,
Wendong
Wang
,
Sam
Sullivan-Allsop
,
Xiao
Li
,
Astrid
Weston
,
Eli G.
Castanon
,
Andrey V.
Kretinin
,
Cephise
Cacho
,
Neil R.
Wilson
,
Sarah J.
Haigh
,
Roman
Gorbachev
Diamond Proposal Number(s):
[21597, 21981, 24290, 24338]
Open Access
Abstract: Magnetic two-dimensional materials are a promising platform for novel nano-electronic device architectures. One such layered crystal is the ferromagnetic semiconductor chromium germanium telluride (Cr2Ge2Te6) which recently attracted interest due to its potential for spintronics and memory applications. Here we investigate its properties from the structural standpoint using atomic resolution Scanning Transmission Electron Microscopy (STEM) and present the first atomic resolution images down to its monolayer limit. We develop a novel technique that allows one to map the local tilt with unprecedented spatial resolution using only high-resolution images, enabling mapping of the topography and morphological variation of atomically thin crystals. Using it, we show that the Cr2Ge2Te6 monolayer has an unusually large out-of-plane rippling, with local tilt variation reaching 20° over few nm length scales. We hypothesize that such a strongly buckled structure originates from both point and extended lattice defects which are more prevalent in monolayer crystals. In addition, we correlate the structural observations with the band structure measurements using Angle-Resolved Photoemission Spectroscopy (ARPES). We believe that both the atomic scale insights we have gained on Cr2Ge2Te6 and our novel approach to nanoscale topography mapping will benefit the development of van der Waals heterostructures in both fundamental and applied research.
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Feb 2026
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E02-JEM ARM 300CF
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Wendong
Wang
,
Gareth R.
Tainton
,
Nicholas J.
Clark
,
James G.
Mchugh
,
Xue
Li
,
Sam
Sullivan-Allsop
,
David G.
Hopkinson
,
Oldrich
Cicvárek
,
Francisco
Selles
,
Rui
Zhang
,
Joshua D.
Swindell
,
Alex
Summerfield
,
David J.
Lewis
,
Vladimir I.
Fal'Ko
,
Zdenek
Sofer
,
Sarah
Haigh
,
Roman
Gorbachev
Diamond Proposal Number(s):
[39088]
Abstract: Transition metal diiodides such as FeI2, NiI2, and CoI2 are an emerging class of 2D magnets exhibiting rich and diverse magnetic behavior, but their study at the monolayer limit has been severely hindered by fabrication challenges due to their air-sensitivity. Here, we introduce a polymer-free method for clean, rapid, and high-yield assembly of hermetically encapsulated suspended samples of air-sensitive monolayers. Applied to diiodides, it enables atomic resolution characterization of thin samples down to the monolayer limit using transmission electron microscopy. Our imaging, combined with complementary first-principles calculations, reveals an unusually small energy barrier between alternate stable stacking polytypes in few-layer films, enabling extrinsic control of the stacking phase. We also observe stable isolated iodine vacancies that do not aggregate to form extended structures and identify and verify the stability of the various edge configurations of thin samples. These results establish the structural characteristics of these materials in the thin limit and more broadly demonstrate the utility of our transfer platform for creating atomically clean suspended van der Waals heterostructures.
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Jan 2026
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E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[33252]
Open Access
Abstract: The Noise2Void technique is demonstrated for successful denoising of atomic resolution scanning transmission electron microscopy (STEM) images. The technique is applied to denoising atomic resolution images and videos of gold adatoms on a graphene surface within a graphene liquid-cell, with the denoised experimental data qualitatively demonstrating improved visibility of both the Au adatoms and the graphene lattice. The denoising performance is quantified by comparison to similar simulated data and the approach is found to significantly outperform both total variation and simple Gaussian blurring. Compared to other denoising methods, the Noise2Void technique has the combined advantages that it requires no manual intervention during training or denoising, no prior knowledge of the sample and is compatible with real-time data acquisition rates of at least 45 frames per second.
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Jan 2026
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E02-JEM ARM 300CF
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Evan David Innes
Tillotson
,
William
Thornley
,
William
Talbott
,
Alexander S.
Eggeman
,
Daria
Kriuchkova
,
Sam
Sullivan-Allsop
,
Matthew
Smith
,
Xuzhao
Liu
,
Ashley
Slattery
,
Pei Lay
Yap
,
Dusan
Losic
,
Zhun
Xu
,
Huan
Wang
,
Jim
Ciston
,
Alexander
Rakowski
,
Stephanie M.
Ribet
,
Benjamin H
Savitzky
,
Manfred Erwin
Schuster
,
Christopher S.
Allen
,
Danielle
Douglas-Henry
,
Valeria
Nicolosi
,
Andrew
Herzing
,
Jacques
O'Connell
,
Ezra J.
Olivier
,
Jan
Neethling
,
Yichao
Zou
,
Ercin Cagan
Duran
,
Rongsheng
Cai
,
Duc-The
Ngo
,
Roman
Gorbachev
,
Jonas
Haas
,
Michael
Schlegel
,
Jannik C.
Meyer
,
Alba
Centeno
,
Amaia
Pesquera
,
Amaia
Zurutuza
,
Sungsu
Kang
,
Jungwon
Park
,
Ivan
Erofeev
,
Utkur
Mirsaidov
,
Colin
Ophus
,
Christian
Rentenberger
,
Thomas
Waitz
,
Jani
Kotakoski
,
Abhijit
Roy
,
Raul
Arenal
,
Andrew
Pollard
,
Sarah
Haigh
Diamond Proposal Number(s):
[29951]
Open Access
Abstract: Standardisation of data collection and analysis is essential to enable commercialisation of 2D materials in a wide range of technologies. Selected area electron diffraction (SAED) in the transmission electron microscope (TEM) is one of the key methods for distinguishing monolayer from bilayer and few-layer graphene by comparing the 1st and 2nd order diffraction spot intensities. Yet there are many factors that can affect the reliability of data collection and interpretation, causing the measurement of monolayer samples to deviate from the literature boundary condition of I{-2110}/I{1-100}<1 for monolayer graphene. Here we present the results of a large interlaboratory SAED comparison study, where 15 international laboratories measured and analysed nominally identical samples of chemical vapour deposited (CVD) graphene. Large variations were observed in the measured ratios of diffraction spot intensities, with the largest variance associated with poor quality SAED data resulting from poor specimen handling and storage. To inform the reliable determination of monolayer thickness from SAED patterns we provide a description of best practice for specimen handling, TEM operation, data collection and analysis. This work was undertaken within VAMAS Technical Working Area (TWA) 41: Graphene and related 2D materials - Project 9, the results of which have been directly incorporated into ISO/TS 21356-2 for the characterisation of graphene sheets. We find that when this methodology is followed, monolayer graphene can be distinguished from bilayer or thicker material with high confidence where analysis of a single SAED pattern gives I{-2110}/I{1-100}<1.2, even in the absence of precise specimen tilting.
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Dec 2025
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E02-JEM ARM 300CF
I09-Surface and Interface Structural Analysis
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Benedikt P.
Klein
,
Matthew A.
Stoodley
,
Joel
Deyerling
,
Luke A.
Rochford
,
Dylan B.
Morgan
,
David G.
Hopkinson
,
Sam
Sullivan-Allsop
,
Henry
Thake
,
Fulden
Eratam
,
Lars
Sattler
,
Sebastian M.
Weber
,
Gerhard
Hilt
,
Alexander
Generalov
,
Alexei
Preobrajenski
,
Thomas
Liddy
,
Leon B. S.
Williams
,
Mhairi A.
Buchan
,
Graham A
Rance
,
Tien-Lin
Lee
,
Alex
Saywell
,
Roman
Gorbachev
,
Sarah J.
Haigh
,
Christopher S.
Allen
,
Willi
Auwärter
,
Reinhard
Maurer
,
David A.
Duncan
Diamond Proposal Number(s):
[25379, 30875, 31695, 31165, 33709]
Open Access
Abstract: Chemical vapour deposition enables large-domain growth of ideal graphene, yet many applications of graphene require the controlled inclusion of specific defects. We present a one-step chemical vapour deposition procedure aimed at retaining the precursor topology when incorporated into the grown carbonaceous film. When azupyrene, the molecular analogue of the Stone–Wales defect in graphene, is used as a precursor, carbonaceous monolayers with a range of morphologies are produced as a function of the copper substrate growth temperature. The higher the substrate temperature during deposition, the closer the resulting monolayer is to ideal graphene. Analysis, with a set of complementary materials characterisation techniques, reveals morphological changes closely correlated with changes in the atomic adsorption heights, network topology, and concentration of 5-/7-membered carbon rings. The engineered defective carbon monolayers can be transferred to different substrates, potentially enabling applications in nanoelectronics, sensorics, and catalysis.
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Sep 2025
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I05-ARPES
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Diamond Proposal Number(s):
[20573, 28919, 32737]
Open Access
Abstract: Diverse emergent correlated electron phenomena have been observed in twisted-graphene layers. Many electronic structure predictions have been reported exploring this new field, but with few momentum-resolved electronic structure measurements to test them. We use angle-resolved photoemission spectroscopy to study the twist-dependent (1° < θ < 8°) band structure of twisted-bilayer, monolayer-on-bilayer, and double-bilayer graphene (tDBG). Direct comparison is made between experiment and theory, using a hybrid k·p model for interlayer coupling. Quantitative agreement is found across twist angles, stacking geometries, and back-gate voltages, validating the models and revealing field-induced gaps in twisted graphenes. However, for tDBG at θ = 1.5 ± 0.2°, close to the magic angle θ = 1.3°, a flat band is found near the Fermi level with measured bandwidth Ew = 31 ± 5 meV. An analysis of the gap between the flat band and the next valence band shows deviations between experiment (Δh = 46 ± 5 meV) and theory (Δh = 5 meV), indicative of lattice relaxation in this regime.
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May 2023
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E02-JEM ARM 300CF
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Yi-Chao
Zou
,
Lucas
Mogg
,
Nick
Clark
,
Cihan
Bacaksiz
,
Slavisa
Milanovic
,
Vishnu
Sreepal
,
Guang-Ping
Hao
,
Yi-Chi
Wang
,
David G.
Hopkinson
,
Roman
Gorbachev
,
Samuel
Shaw
,
Kostya S.
Novoselov
,
Rahul
Raveendran-Nair
,
Francois M.
Peeters
,
Marcelo
Lozada-Hidalgo
,
Sarah
Haigh
Diamond Proposal Number(s):
[21981, 21597]
Abstract: The physical properties of clays and micas can be controlled by exchanging ions in the crystal lattice. Atomically thin materials can have superior properties in a range of membrane applications, yet the ion-exchange process itself remains largely unexplored in few-layer crystals. Here we use atomic-resolution scanning transmission electron microscopy to study the dynamics of ion exchange and reveal individual ion binding sites in atomically thin and artificially restacked clays and micas. We find that the ion diffusion coefficient for the interlayer space of atomically thin samples is up to 104 times larger than in bulk crystals and approaches its value in free water. Samples where no bulk exchange is expected display fast exchange at restacked interfaces, where the exchanged ions arrange in islands with dimensions controlled by the moiré superlattice dimensions. We attribute the fast ion diffusion to enhanced interlayer expandability resulting from weaker interlayer binding forces in both atomically thin and restacked materials. This work provides atomic scale insights into ion diffusion in highly confined spaces and suggests strategies to design exfoliated clay membranes with enhanced performance.
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Aug 2021
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E02-JEM ARM 300CF
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Diamond Proposal Number(s):
[19315, 21597]
Abstract: Suspended specimens of 2D crystals and their heterostructures are required for a range of studies including transmission electron microscopy (TEM), optical transmission experiments and nanomechanical testing. However, investigating the properties of laterally small 2D crystal specimens, including twisted bilayers and air sensitive materials, has been held back by the difficulty of fabricating the necessary clean suspended samples. Here we present a scalable solution which allows clean free-standing specimens to be realized with 100% yield by dry-stamping atomically thin 2D stacks onto a specially developed adhesion-enhanced support grid. Using this new capability, we demonstrate atomic resolution imaging of defect structures in atomically thin CrBr3, a novel magnetic material which degrades in ambient conditions.
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Aug 2020
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E02-JEM ARM 300CF
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Astrid
Weston
,
Yichao
Zou
,
Vladimir
Enaldiev
,
Alex
Summerfield
,
Nicholas
Clark
,
Viktor
Zólyomi
,
Abigail
Graham
,
Celal
Yelgel
,
Samuel
Magorrian
,
Mingwei
Zhou
,
Johanna
Zultak
,
David
Hopkinson
,
Alexei
Barinov
,
Thomas H.
Bointon
,
Andrey
Kretinin
,
Neil R.
Wilson
,
Peter H.
Beton
,
Vladimir I.
Fal’ko
,
Sarah J.
Haigh
,
Roman
Gorbachev
Diamond Proposal Number(s):
[19315, 21597]
Abstract: Van der Waals heterostructures form a unique class of layered artificial solids in which physical properties can be manipulated through controlled composition, order and relative rotation of adjacent atomic planes. Here we use atomic-resolution transmission electron microscopy to reveal the lattice reconstruction in twisted bilayers of the transition metal dichalcogenides, MoS2 and WS2. For twisted 3R bilayers, a tessellated pattern of mirror-reflected triangular 3R domains emerges, separated by a network of partial dislocations for twist angles θ < 2°. The electronic properties of these 3R domains, featuring layer-polarized conduction-band states caused by lack of both inversion and mirror symmetry, appear to be qualitatively different from those of 2H transition metal dichalcogenides. For twisted 2H bilayers, stable 2H domains dominate, with nuclei of a second metastable phase. This appears as a kagome-like pattern at θ ≈ 2°, transitioning at θ → 0 to a hexagonal array of screw dislocations separating large-area 2H domains. Tunnelling measurements show that such reconstruction creates strong piezoelectric textures, opening a new avenue for engineering of 2D material properties.
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May 2020
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