Article
Chemistry, Multidisciplinary
Shanquan Chen, Jhong-Yi Chang, Qinghua Zhang, Qiuyue Li, Ting Lin, Fanqi Meng, Haoliang Huang, Yangyang Si, Shengwei Zeng, Xinmao Yin, My Ngoc Duong, Yalin Lu, Lang Chen, Er-Jia Guo, Hanghui Chen, Chun-Fu Chang, Chang-Yang Kuo, Zuhuang Chen
Summary: The spin state of Co ions in epitaxial LaCoO3 thin films under tensile strain has been determined to have mixed high-spin and low-spin states, while it is practically a low-spin state under compressive strain. The identification of this spin state ratio explains the origin of ferromagnetism in LaCoO3 films. This study highlights the importance of spin state degrees of freedom and thin-film strain engineering in creating new physical properties that do not exist in bulk materials.
Article
Chemistry, Physical
Tao Wang, Zhuokai Xu, Ziye Zhu, Mengqi Wu, Zhefeng Lou, Jialu Wang, Wanghua Hu, Xiaohui Yang, Tulai Sun, Xiaorui Zheng, Wenbin Li, Xiao Lin
Summary: Bi2O2Se is a highly competitive candidate for next-generation high-performance semiconductors. Researchers have successfully synthesized highly insulating films with semiconducting behavior, providing valuable insights into the electron dynamics of Bi2O2Se and offering a platform for engineering ferroelectricity in high-performance semiconductors.
Article
Chemistry, Physical
Tao Wang, Zhuokai Xu, Ziye Zhu, Mengqi Wu, Zhefeng Lou, Jialu Wang, Wanghua Hu, Xiaohui Yang, Tulai Sun, Xiaorui Zheng, Wenbin Li, Xiao Lin
Summary: Bi2O2Se is a highly competitive candidate for next-generation high-performance semiconductors. In this study, we synthesized highly insulating films of Bi2O2Se that exhibit semiconducting behavior. Our work provides insights into the electron dynamics of Bi2O2Se, and moves closer towards the development of p-type transistors and engineering ferroelectricity in high-performance semiconductors.
Article
Chemistry, Physical
Sergio Tosoni, Gianfranco Pacchioni
Summary: This study investigates the magnetic ground state and hyperfine coupling parameters of first-row transition metal atoms adsorbed on ultrathin insulating oxide films using DFT calculations. The results highlight the challenges in calculating hyperfine coupling constants and the dependence on the magnetic state and electron configuration of the metal atoms. The role of the metal support is also emphasized, as it can significantly influence the hyperfine coupling constants and have important implications for applications in quantum technologies or memory devices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Sergei Ivanov, Joshua Peacock, Sergei Urazhdin
Summary: We propose a two-orbital Hubbard model for explaining electron correlations in ultrathin (111)-oriented fcc films of late transition metals. Our findings show that the Mott-Hund's interaction leads to ferromagnetic nearest-neighbor orbital correlations. However, due to frustration caused by the mismatch between orbital and crystal symmetries, orbital ordering is inhibited, resulting in the orbital liquid state. This state can be observed in phenomena related to spin-orbit coupling, such as magnetic anisotropy.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Chemistry, Physical
Gian Marco Pierantozzi, Giovanni Vinai, Aleksandr Yu Petrov, Alessandro De Vita, Federico Motti, Vincent Polewczyk, Debashis Mondal, Tommaso Pincelli, Riccardo Cucini, Chiara Bigi, Ivana Vobornik, Jun Fujii, Piero Torelli, Francesco Offi, Giorgio Rossi, Giancarlo Panaccione, Francesco Borgatti
Summary: In this study, the relationship between ferromagnetism and metallicity in strained La0.67Ca0.33MnO3 films was investigated. It was found that the half-metallicity of the ferromagnetic metallic (FMM) phase is correlated with spin polarization and occupancy at the Fermi level. These results suggest that the half-metallic behavior predicted by a double-exchange model persists even in phase-separated manganites.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Materials Science, Multidisciplinary
Hongwei Cheng, Hongliang Chen, Chao Jin, Haili Bai
Summary: To modulate the properties of antiferromagnetic (AFM) materials, La0.92Sr0.08MnO3 (LSMO) films were deposited on different substrates, showing AFM metallic, AFM insulating, and ferromagnetic (FM) insulating states. The temperature-dependent Raman spectra revealed that the FM state of LSMO/MgO resulted from lattice distortion caused by large lattice mismatch. The LSMO/STO and LSMO/LAO films exhibited metal-insulator transitions (MIT) at different temperatures due to electron-phonon coupling induced by lattice distortion.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Article
Materials Science, Coatings & Films
Nisha Thankachen, Bhargav Y. Pathak, Rutvi J. Pandya, U. V. Chhaya, A. K. Debnath, U. S. Joshi
Summary: This article investigates the influence of the Co/Mn ratio on the physical properties of the type II multiferroic material Ca3CoMnO6 thin films. The experimental results show that Fe substitution decreases the bandgap and enhances the magnetoresistance and magnetodielectric coupling effects in CCMO thin films.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Chemistry, Multidisciplinary
Lakhan Bainsla, Akash Kumar, Ahmad A. Awad, Chunlei Wang, Mohammad Zahedinejad, Nilamani Behera, Himanshu Fulara, Roman Khymyn, Afshin Houshang, Jonas Weissenrieder, Johan Akerman
Summary: This study investigates the characteristics of ultrathin ferrimagnetic films, and for the first time, observes nearly compensated behavior in 2 nm thick Gd-x(Fe87.5Co12.5)(1-x) films, showing great potential for the development of ultrafast and energy efficient ferrimagnetic spintronic devices.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Multidisciplinary Sciences
Jinwoong Hwang, Kyoo Kim, Canxun Zhang, Tiancong Zhu, Charlotte Herbig, Sooran Kim, Bongjae Kim, Yong Zhong, Mohamed Salah, Mohamed M. El-Desoky, Choongyu Hwang, Zhi-Xun Shen, Michael F. Crommie, Sung-Kwan Mo
Summary: In this study, the authors demonstrate the emergence of an insulating dimer ground state in monolayer 1T-IrTe2. The findings provide insights into the balance of interactions in the absence of interlayer coupling and offer new opportunities for engineering the properties of two-dimensional monolayers.
NATURE COMMUNICATIONS
(2022)
Article
Mechanics
Satya Sekhar, V. Shankar
Summary: This study investigates the linear stability of freestanding thin films under the influence of attractive van der Waals forces, comparing three rheological models and finding that thin freestanding viscous films are unconditionally unstable, while elasticity plays different roles in the stability of solid and liquid films. The linear stability of Jeffreys viscoelastic freestanding films is compared with supported films in the inertialess limit, showing that the instability is unaffected by relaxation time but enhanced with a decrease in viscosity ratio.
Article
Multidisciplinary Sciences
Xiaoqian Zhang, Qiangsheng Lu, Wenqing Liu, Wei Niu, Jiabao Sun, Jacob Cook, Mitchel Vaninger, Paul F. Miceli, David J. Singh, Shang-Wei Lian, Tay-Rong Chang, Xiaoqing He, Jun Du, Liang He, Rong Zhang, Guang Bian, Yongbing Xu
Summary: Growth and properties of single- and few-layer CrTe2 on bilayer graphene by molecular beam epitaxy (MBE) have shown intrinsic ferromagnetism with a Curie temperature up to 300 K and perpendicular magnetic anisotropy, providing a new avenue for developing large-scale 2D magnet-based spintronics devices.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
S. Passanante, L. P. Granja, C. Albornoz, D. Vega, D. Goijman, M. C. Fuertes, C. Ferreyra, L. Ghivelder, F. Parisi, M. Quintero
Summary: The magnetic and magnetocaloric properties of bilayers and single layer manganite thin films were studied, and it was found that the bilayers can broaden the temperature range of the magnetocaloric effect without reducing the refrigerant capacity, offering potential for refrigeration device applications.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Multidisciplinary Sciences
Zhiwei Jiang, Ruijiao Dong, Austin M. Evans, Niklas Biere, Mahmood A. Ebrahim, Siyao Li, Dario Anselmetti, William R. Dichtel, Andrew G. Livingston
Summary: In this study, we successfully created ordered pores in an ultra-thin nanofilm by synthesizing selectively functionalized macrocycles with differentiated reactivities. The size of the subnanometre macrocycle pores in the nanofilm surfaces could be precisely tailored by varying the macrocycle identity. Compared to disordered membranes, aligned macrocycle membranes exhibited higher permeance and selectivity. In high-value separations, such as enriching cannabidiol oil, the aligned macrocycle membranes achieved significantly faster ethanol transport and higher enrichment.
Article
Chemistry, Physical
H. Samet Varol, Tilmann Herberger, Marius Kirsch, Joanna Mikolei, Lothar Veith, Venkataprasanna Kannan-Sampathkumar, Raoul D. Brand, Christopher V. Synatschke, Tanja Weil, Annette Andrieu-Brunsen
Summary: This study investigates the electropolymerization of homogeneous thin PDA films to functionalize nanopores of mesoporous silica films. The amount and location of deposited PDA at mesoporous films is related to the combination of the number of electropolymerization cycles and the mesoporous film structure. The pH-dependent deprotonation of PDA and silica walls and the insulation of the ITO surface by increasing the amount of PDA within the mesoporous silica film affect the ionic nanopore transport.
CHEMISTRY OF MATERIALS
(2023)
Article
Multidisciplinary Sciences
Seung Sae Hong, Mingqiang Gu, Manish Verma, Varun Harbola, Bai Yang Wang, Di Lu, Arturas Vailionis, Yasuyuki Hikita, Rossitza Pentcheva, James M. Rondinelli, Harold Y. Hwang
Article
Chemistry, Multidisciplinary
Varun Harbola, Samuel Crossley, Seung Sae Hong, Di Lu, Yorick A. Birkholzer, Yasuyuki Hikita, Harold Y. Hwang
Summary: Young's modulus plays a crucial role in determining the mechanical behavior of materials, particularly in flexoelectric materials where the modulus may vary nonmonotonically with thickness and be influenced by strain gradients. Nanomechanical measurements of SrTiO3 crystalline membrane drumheads reveal unexpected thickness dependence of Young's modulus, with significantly different values obtained for predominantly bending and stretching deformations in membranes thinner than 20 nm. In this regime, a strain gradient elastic coupling of around 2.2 µN is extracted, suggesting potential applications in new operational regimes of nanoelectro-mechanics.
Article
Physics, Multidisciplinary
Carl Willem Rischau, Yuke Li, Benoit Fauque, Hisashi Inoue, Minu Kim, Christopher Bell, Harold Y. Hwang, Aharon Kapitulnik, Kamran Behnia
Summary: The study demonstrates that in different types of superconductors, the Nernst signal corresponds to an entropy per vortex per layer of approximately k(B)ln2. The amplitude of the Nernst signal generated by ephemeral Cooper pairs above the critical temperature matches the theoretical expectations.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Zhuoyu Chen, Bai Yang Wang, Adrian G. Swartz, Hyeok Yoon, Yasuyuki Hikita, Srinivas Raghu, Harold Y. Hwang
Summary: Anomalous metallic behavior with saturating finite resistivity has been observed in a wide range of two-dimensional superconductors. The study finds that the anomalous metal phases induced by gating and magnetic field, although different in symmetry, are connected in the phase diagram and exhibit similar magnetic field response approaching zero temperature. This universal behavior highlights the uniqueness of the quantum bosonic metallic state.
NPJ QUANTUM MATERIALS
(2021)
Article
Chemistry, Physical
Motoki Osada, Kazunori Nishio, Kyuho Lee, Michael Colletta, Berit H. Goodge, Woo Jin Kim, Lena F. Kourkoutis, Harold Y. Hwang, Yasuyuki Hikita
Summary: The research presents the first photoelectrochemical characterization of epitaxial thin film Fe2TiO5, revealing highly efficient charge transfer at the Fe2TiO5-electrolyte interface. This notable surface property is exploited in the form of an Fe2TiO5/alpha-Fe2O3 heterostructure photoanode, leading to a significant increase in photocurrent density and improvement in onset potential.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Danfeng Li, Carolina Adamo, Bai Yang Wang, Hyeok Yoon, Zhuoyu Chen, Seung Sae Hong, Di Lu, Yi Cui, Yasuyuki Hikita, Harold Y. Hwang
Summary: A new synthetic approach has been developed for freestanding crystalline perovskite oxide nanomembranes using a water-soluble sacrificial layer. By utilizing a thin capping layer of SrTiO3, the sacrificial layer can be stabilized and used as transferable templates for ex situ epitaxial growth. This study enables the synthesis of a wider selection of freestanding oxide membranes and heterostructures using various ex situ growth techniques.
Article
Materials Science, Multidisciplinary
D. Chaney, A. Castellano, A. Bosak, J. Bouchet, F. Bottin, B. Dorado, L. Paolasini, S. Rennie, C. Bell, R. Springell, G. H. Lander
Summary: This study conducted extensive X-ray scattering analysis on the stable alloy U1-xMox, revealing a new form of tunable correlated disorder and a strong disorder-phonon coupling mechanism. These findings offer a new design strategy for phonon engineering and can be crucial in the development of future functional materials.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Chemistry, Physical
Kyuho Lee, Raul A. Flores, Yunzhi Liu, Bai Yang Wang, Yasuyuki Hikita, Robert Sinclair, Michal Bajdich, Harold Y. Hwang
Summary: This study demonstrates the growth of alpha-IrO2 epitaxial thin films using pulsed laser deposition, showing that crystal orientation significantly affects the electrocatalytic activity. The results suggest that epitaxial thin film growth can overcome energetic instabilities and provide unique opportunities to effectively determine the atomic structure of active catalysts.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Micha Ben-Naim, Yunzhi Liu, Michaela Burke Stevens, Kyuho Lee, Melissa R. Wette, Alexey Boubnov, Artem A. Trofimov, Anton V. Ievlev, Alex Belianinov, Ryan C. Davis, Bruce M. Clemens, Simon R. Bare, Yasuyuki Hikita, Harold Y. Hwang, Drew C. Higgins, Robert Sinclair, Thomas F. Jaramillo
Summary: This study investigates the stability of SrIrO3 thin film electrocatalyst materials using advanced nanoscale microscopy techniques and complementary structural and chemical characterization. Accelerated degradation tests under anodic potential show thinning and roughening of the SrIrO3 film, while the lateral distribution of Sr and Ir remains homogeneous. A layer-wise dissolution mechanism is hypothesized, shedding light on the stability of this electrocatalyst.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Multidisciplinary Sciences
Ismail El Baggari, David J. Baek, Michael J. Zachman, Di Lu, Yasuyuki Hikita, Harold Y. Hwang, Elizabeth A. Nowadnick, Lena F. Kourkoutis
Summary: The study demonstrates the capability of cryogenic scanning transmission electron microscopy in directly mapping the local arrangements and symmetries of electronic order, providing a useful method for studying strongly correlated systems. Using Nd1/2Sr1/2MnO3 as an example, the authors show the nanoscale coexistence of an exotic intermediate state and the importance of lattice coupling in controlling the selection between competing ground states.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Rebecca Nicholls, Chris Bell, Ross Springell, Gerard H. Lander, Johann Bouchet
Summary: We report a simple technique for synthesizing uniaxially textured uranium thin films and investigate the crystallographic orientations and transitions of the films. The results show that the final orientations and timescales of the transitions depend on the lattice parameters of the original layer.
PHYSICAL REVIEW MATERIALS
(2022)
Review
Physics, Condensed Matter
R. Springell, E. Lawrence Bright, D. A. Chaney, L. M. Harding, C. Bell, R. C. C. Ward, G. H. Lander
Summary: Thin films based on silicon and transition-metal elements are widely used in the semiconductor industry. Films of rare-earth series elements have also been applied for research and specific applications. This review covers the recent work on uranium and uranium dioxide thin films, including their fabrication, interaction with substrates, and various experiments. Possible future prospects, such as uranium-containing bilayers for spintronics and superlattices for heterostructures, are also discussed.
ADVANCES IN PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
M. N. Rizwan, C. Bell, M. A. Kalyar, A. R. Makhdoom, A. Ul Haq, E. Gilory
Summary: Nickel thin films were deposited on silicon (100) substrates by pulsed laser deposition at various substrate temperatures, revealing variations in grain size and roughness with temperature, along with the presence of nickel phases in the range of 100-300 degrees Celsius.
JOURNAL OF OVONIC RESEARCH
(2021)
Article
Materials Science, Multidisciplinary
E. R. Gilroy, M-H Wu, M. Gradhand, R. Springell, C. Bell
Summary: Magnetometry measurements of Fe/U and Ni/U bilayer systems show a nonmonotonic dependence of magnetic anisotropy on U thicknesses, with Fe/U exhibiting a more prominent effect. This is attributed to stronger 3d-5f hybridization between Fe and U. The nonmonotonic behavior is thought to stem from quantum well states in uranium overlayers, with indications of perpendicular magnetic anisotropy in a subset of Fe/U samples at relatively large U thickness.
Article
Nanoscience & Nanotechnology
M. Nawaz Rizwan, M. A. Kalyar, C. Bell, M. Anwar-Ul-Haq, A. R. Makhdoom
DIGEST JOURNAL OF NANOMATERIALS AND BIOSTRUCTURES
(2020)
