B16-Test Beamline
|
Diamond Proposal Number(s):
[36299, 34545]
Open Access
Abstract: This study investigates the lattice strain induced by Ge:Sb alloy films on Ge substrates. Metastable films are formed by UV pulsed laser melting (PLM) of a Sb-coated Ge substrate. We fabricate thin Ge:Sb layers, systematically varying processing parameters and crystal orientation to study strain and strain-relaxation-induced defects. High-resolution X-Ray diffraction and electrical characterization revealed extremely high strain values as well as ultra-low resistivity induced by Sb. Maximum strain before the onset of strain relaxation was found to depend on crystal orientation with the Ge (1 1 1) orientation yielding the highest strain values. By combining structural as well as electrical information, we estimated Sb contribution to lattice expansion, separating electronically active from inactive fractions. Strain optimization was applied to an innovative application that is the production of bent crystals for high energy particle beam deflection and radiation production. Bending tests on thin Ge substrates confirmed the method, with controlled PLM processing allowing inducing quantifiable curvature with smallest achievable radii of 4.5 m. Exploiting non-equilibrium doping/alloying to exceed equilibrium Sb solubility is promising for applications ranging from ultra-low-resistivity layers in scaled nano-electronic devices to bent crystals for advanced systems like crystal-based undulators, enabling new approaches to high-energy photon production.
|
Jun 2026
|
|
I06-Nanoscience (XPEEM)
|
Weican
Lan
,
Chaocheng
Liu
,
Yajuan
Feng
,
Ruiqi
Liu
,
Yafei
Chu
,
Lu
Cheng
,
Chao
Wang
,
Huijuan
Wang
,
Minghui
Fan
,
Zixun
Zhang
,
Yuran
Niu
,
Jheng-Cyuan
Lin
,
Francesco
Maccherozzi
,
Hengli
Duan
,
Wensheng
Yan
Diamond Proposal Number(s):
[40612]
Abstract: Excitons are primary elementary excitations in solids that present both fundamental interest and technological importance, showing great potential for photospintronic and quantum transduction applications. The emerging coherent collective excitations in two-dimensional antiferromagnetic semiconductors raise prospects for spin-exciton interactions and multifield control schemes. However, realizing the arbitrary manipulation of excitonic quantum states, while preserving the inherent dynamic and response advantages of antiferromagnetic nature remains challenging. Here we achieve bidirectional modulation of the CrSBr exciton energy via interfacial interaction-modified spin-exciton coupling in a CrSBr/Fe3GaTe2 heterostructure. Compared with pristine CrSBr, the photoluminescence peaks in the heterostructure can exhibit blueshift and redshift corresponding to 6.1% and 8.6% of the total bandwidth, respectively. We reveal that the interfacial charge-transfer-driven magnetic coupling in the heterostructure effectively enhances the magnetic anisotropy and the exchange interaction of CrSBr, thereby stabilizing its antiferromagnetic spin configuration, suppressing interlayer electron-hole recombination, and ultimately leading to an anomalous blueshift of the exciton emission. Our findings demonstrate an approach for bidirectionally modulating exciton energy in two-dimensional antiferromagnetic semiconductors, which provides substantial flexibility in device design and offers an avenue for potential wavelength control in quantum information and optoelectronic technologies.
|
Feb 2026
|
|
|
|
Sanghyo
Lee
,
Sojin
Kim
,
Jinseok
Ryu
,
Jaewook
Lee
,
Jinseok
Hong
,
Ji Eun
Kim
,
Ju-Young
Cha
,
Yunho
Shin
,
Daewoong
Kwon
,
Jung Ho
Yoon
,
Min Hyuk
Park
,
Miyoung
Kim
,
Seung-Yong
Lee
Abstract: Understanding electric-field-induced phase transitions is crucial for optimizing the ferroelectric and antiferroelectric properties of hafnium zirconium oxide (Hf0.5Zr0.5O2, HZO) thin films. Here, we use in situ transmission electron microscopy (TEM) to uncover the nanoscale mechanism of field-induced phase evolution in ultrathin HZO films at the morphotropic phase boundary (MPB), directly visualizing oxygen vacancy migration and its correlation with the transformation from the nonpolar tetragonal to polar orthorhombic phase. Our in situ TEM setup applied sub-100 μs bipolar voltage pulses, mimicking real device operation while allowing the detection of the subtle changes induced by such short pulses. Unsupervised machine learning analysis of electron energy-loss spectroscopy spectrum images (EELS-SIs) revealed distinct spectral features associated with local structural evolution, with quantitative results confirming oxygen-deficient regions aligned with orthorhombic phase formation. Unlike conventional TEM studies confined to a few nanoscale domains, this approach enables film-scale interpretation of phase evolution, capturing broader trends beyond isolated observations. Concurrent oxygen content changes in the TiN electrode further indicate active vacancy exchange between HZO and TiN under bias. These findings directly link oxygen vacancy dynamics to polarization switching, offering critical guidance for stabilizing ferroelectric phases and advancing next-generation memory and logic devices.
|
Feb 2026
|
|
I05-ARPES
|
Oliver J.
Clark
,
Anugrah
Azhar
,
Thi-Hai-Yen
Vu
,
Benjamin A.
Chambers
,
Federico
Mazzola
,
Sadhana
Sridhar
,
Geetha
Balakrishnan
,
Aaron
Bostwick
,
Chris
Jozwiak
,
Eli
Rotenberg
,
Sarah L.
Harmer
,
Mohammad Saeed
Bahramy
,
Michael S.
Fuhrer
,
Mark T.
Edmonds
Diamond Proposal Number(s):
[40610]
Open Access
Abstract: Discovering and engineering spin-polarized surface states in the electronic structures of condensed matter systems is a crucial first step in the development of spintronic devices, wherein spin-polarized bands crossing the Fermi level can facilitate information transfer. Here, through nanofocused angle-resolved photoemission spectroscopy (nano-ARPES) and density functional theory-based calculations, we show that the interface between monolayer WSe2 and metallic NbSe2 exhibits a negative Schottky barrier height of ∼ −30 meV: the K-point valleys of the semiconducting layer are shifted by ∼800 meV to produce a surface-localized Fermi surface populated only by spin-polarized charge carriers. By increasing the WSe2 thickness, the Fermi pockets can be moved from K to Γ, demonstrating tunability of novel semimetallic phases that exist atop a substrate additionally possessing charge density wave and superconducting phases. Together, this study provides a spectroscopic understanding into p-type, Schottky barrier-free interfaces, which are of urgent interest for bypassing the limitations of current-generation vertical field effect transistors, in addition to longer-term spintronics development.
|
Feb 2026
|
|
I10-Beamline for Advanced Dichroism - scattering
|
Diamond Proposal Number(s):
[36197]
Abstract: Heterostructures composed of heavy metal and van der Waals (vdW) magnets serve as platforms to investigate magnetotransport properties, enabling the electric readout of the spin-flop transition in the vdW antiferromagnet. We investigate the spin and orbital contributions to magnetism in Pt/exfoliated multilayer CrPS4 heterostructure using the synchrotron-radiation based x-ray magnetic circular dichroism technique measured in the total electron yield (TEY) mode. The TEY detection, with probing depth of 5–10 nm, mainly reflects the interfacial magnetic behavior near the Pt/CrPS4 boundary. A spin-flop transition appears near 0.7 T in both the CrPS4 single crystal and the Pt/CrPS4 heterostructures. The total Cr moment remains ∼2 μB/f.u. in both systems at 14 T and 6 K. In Pt/CrPS4, the orbital moment is strongly modulated by Pt, as manifested in the enhancement from ∼0.1 μB/f.u. in CrPS4 to ∼0.5 μB/f.u. in Pt/CrPS4, an effect attributable to the strong spin–orbit coupling with Pt. At 25 K, the total Cr moment reduces to ∼1.1 μB/f.u. in both systems. The Cr orbital moment in CrPS4 remains low ∼0.1 μB/f.u., whereas in Pt/CrPS4 it remains high ∼0.5 μB/f.u. These findings provide qualitative evidence of robust spin–orbit coupling and orbital hybridization at Pt/CrPS4 interface, and highlight the potential of heavy metal/vdW antiferromagnet heterostructures for spin-orbitronic device applications.
|
Feb 2026
|
|
B23-Circular Dichroism
|
Diamond Proposal Number(s):
[36624, 38372]
Open Access
Abstract: Binary mixtures of the ferronematic liquid crystal DIO with the recently reported LC non-ferroelectric material WJ-16 exhibiting Colossal Permittivity (CP) ≈ 5000 and superparaelectricity were studied by POM, electrical switching studies, and dielectric spectroscopy. Three mixtures with different WJ-16 contents ranging from 10, 25 to 50% (w/w) in DIO as host were prepared. Our original expectation was the observations of new nematic compositions with both ferroelectric nematic (N F ) and non-ferroelectric CP phases. We found that the non-ferroelectric phase in mixtures exhibits a CP mode, originally observed in pure WJ-16. The dielectric spectroscopy of mixtures shows two distinct relaxation processes: the typical paraelectric response and the CP mode. Therefore, this CP mode in the mixtures is not superparaelectric and here it is defined as a Hyper-dielectric mode. This is the first direct demonstration of mixtures having both ferroelectric and hyper-dielectric phases in liquid crystalline materials.
|
Feb 2026
|
|
I21-Resonant Inelastic X-ray Scattering (RIXS)
|
Abstract: Understanding the interplay between electronic, magnetic, and lattice degrees of freedom is essential for advancing two-dimensional (2D) van der Waals magnetic ma- terials toward next-generation spintronic and quantum technologies. The magnetic ordering of 2D magnetic compounds is often related to the electronic structure param- eters, such as spin orbit coupling, Hund’s coupling (JH ), p − d covalency, and inter- orbital Coulomb interactions. Accurately determining such parameters is paramount for understanding the physics of these compounds. This thesis presents a compre- hensive study of the electronic structure and low-energy excitations in 2D magnetic material families CrX3 (X = Cl, Br, and I), VX3 (X = Br and I), and CrSBr, using a combination of synchrotron based x-ray absorption spectroscopy, resonant inelas- tic x-ray scattering (RIXS), and state-of-the-art theoretical modeling, together with atomic multiplet simulations.
High-resolution Cr L3−edge RIXS measurements on CrX3 enabled the first clear
experimental energy separation between spin-allowed quartet states and spin-forbidden
doublet states, which increases upon going from CrCl3 to CrI3. The refined crystal-
field and Racah parameters revealed systematic trends in ligand-field strength and
covalency from Cr to I. The RIXS measurements on VX3 revealed a sign opposition
relation between the trigonal distortion parameters ∆ , hence an e′2 ground state in D3d g
VBr and an e′1a1 ground state in VI , consistent with trigonal elongation and com- 3g1g 3
pression, respectively. Momentum-resolved RIXS measurements on CrSBr revealed dispersing multi-phonons along the crystallographic a axis, and only one phonon mode along the b axis, consistent with its quasi-1D behavior. These findings significantly advance fundamental understanding of vdW magnets and provide a strong foundation for future exploration of their potential in spintronics, optoelectronics, and quantum information technologies.
|
Feb 2026
|
|
I07-Surface & interface diffraction
|
Xinyi
Shen
,
Wing Tung
Hui
,
Shuaifeng
Hu
,
Fengning
Yang
,
Junke
Wang
,
Jin
Yao
,
Atse
Louwen
,
Bryan Siu Ting
Tam
,
Lirong
Rong
,
David P.
Mcmeekin
,
Kilian
Lohmann
,
Qimu
Yuan
,
Matthew C.
Naylor
,
Manuel
Kober-Czerny
,
Seongrok
Seo
,
Philippe
Holzhey
,
Karl-Augustin
Zaininger
,
M. Greyson
Christoforo
,
Perrine
Carroy
,
Vincent
Barth
,
Fion Sze Yan
Yeung
,
Nakita K.
Noel
,
Michael
Johnston
,
Yen-Hung
Lin
,
Henry J.
Snaith
Diamond Proposal Number(s):
[39532]
Open Access
Abstract: Vacuum-based deposition is a scalable, solvent-free industrial method ideal for uniform coatings on complex substrates. However, all-vacuum-deposited perovskite solar cells fabricated by thermal evaporation trail solution-processed counterparts in efficiency and stability due to film quality challenges, necessitating advancement and improved understanding. Here, we report a co-evaporation route for 1.67-eV wide-bandgap perovskites by introducing a PbCl2 co-source to optimize film quality. We promote perovskite formation with pronounced (100) ‘face-up’ orientation and deliver a certified all-vacuum-deposited solar cell with 18.35% efficiency (19.3% in the laboratory) for 0.25-cm2 devices (18.5% for 1-cm2 cells). These cells retain 80% of peak efficiency after 1,080 h under the ISOS-L-2 protocol. Leveraging operando hyperspectral imaging, we provide spatiotemporal spectral insight into halide segregation and trap-mediated recombination, correlating microscopic luminescence features with macroscopic device performance while distinguishing radiative from non-ideal recombination channels. We further demonstrate 27.2%-efficient 1-cm2 evaporated perovskite-on-silicon tandem cells and outdoor stability of all-vacuum-deposited tandems in Italy, retaining ~80% initial performance after eight months.
|
Feb 2026
|
|
E02-JEM ARM 300CF
I05-ARPES
|
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.
|
Feb 2026
|
|
I07-Surface & interface diffraction
|
Yuyun
Yao
,
Mustafeez Bashir
Shah
,
Wanpeng
Lu
,
Xian'E
Li
,
Rushil
Vasant
,
Zeinab
Hamid
,
Keren
Ai
,
Junfu
Tian
,
Maryam
Alsufyani
,
Jonathan
Rawle
,
Malina
Gaşpar
,
Qingpei
Wan
,
Rachael
Found
,
Wesley
Chen
,
Tomaž
Kotnik
,
Thuc-Quyen
Nguyen
,
Achilleas
Savva
,
James
Durrant
,
Iain
Mcculloch
Diamond Proposal Number(s):
[39430]
Open Access
Abstract: The development of organic electrochemical transistors (OECTs) critically depends on the design and characterization of mixed-conducting, high-performance conjugated polymers (CPs) as channel materials, particularly for n-type OECTs. In this study, we present a novel strategy to enhance the OECT performance of a semiconducting polymer film via a postdeposition ester pyrolysis of thermally cleavable side chains, thus facilitating ion incorporation and transport within the bulk. Our approach relies on the synthesis of a high glass-transition, rigid-rod polymer, able to withstand the pyrolysis temperature without deformation and maintain the voids formed from the pyrolysis reaction which removes the thermally cleavable ester side chains. After side-chain cleavage, the resulting film exhibits increased porosity, hydrophilicity, and crystallinity. By creating bulk porosity in thin films via this approach, ion diffusion is enhanced, resulting in a superior μC* figure of merit up to 158.85 F cm–1 V–1 s–1, and a corresponding increase in normalized transconductance (31.67 S cm–1). In addition, the device switching speed and long-term stability are also observed to increase, further demonstrating the benefit of nanoscale porosity for mixed conductivity semiconductors.
|
Feb 2026
|
|
