Article
Materials Science, Multidisciplinary
Heike Eisenlohr, Matthias Vojta
Summary: The phenomenology of quantum phase transitions deals with physics at low temperatures and energies, often reaching millikelvin temperatures in solid-state experiments. This study explores how continuous magnetic quantum phase transitions are influenced, modified, or destroyed by the coupling to nuclear spins. Results show the sensitivity of quantum critical systems to small perturbations, affecting the observability of purely electronic quantum criticality at low temperatures.
Article
Chemistry, Multidisciplinary
Chang Qi, Yunyi Wang, Christian Hilty
Summary: Nuclear spin relaxation dispersion parameters can serve as indicators of the binding mode of a ligand to a protein. Hyperpolarization techniques, such as dissolution dynamic nuclear polarization, can provide signal enhancement without the need for isotope enrichment, offering an alternative method for determining ligand binding modes.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Physics, Applied
Yao Chen, Mingzhi Yu, Yintao Ma, Yanbin Wang, Ju Guo, Qijing Lin, Ning Zhang, Zhuangde Jiang, Libo Zhao
Summary: This study investigates the quadrupolar frequency shift of Xe-131 atoms with the silicon wall in a micro-machined vapor cell. The results provide insights into the interaction between Xe-131 nuclear spins and the silicon wall, which are significant for improving the bias stability of atomic spin gyroscopes and studying the surface properties of various materials.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Chemistry, Medicinal
Krys E. A. Batista, Marinalva D. Soares, Marcos G. Quiles, Mauricio J. Piotrowski, Juarez L. F. Da Silva
Summary: The study reveals that changes in the relative stability of transition-metal clusters induced by CO adsorption occur at lower coverages and are mainly influenced by interaction energy and cluster distortion energy. Characterizing all adsorption parameters helps to complement the atomistic understanding of the stability of clusters.
JOURNAL OF CHEMICAL INFORMATION AND MODELING
(2021)
News Item
Physics, Multidisciplinary
Ralf Roehlsberger
Summary: The near-zero thermal expansion of Invar alloy Fe65Ni35 is of technological importance and can be explained by the cancellation of magnetic and phonon contributions to the alloy's entropy.
Article
Materials Science, Ceramics
Mingyang Zhao, Nancy Birkner, Joseph Schaeperkoetter, Robert J. Koch, Patrick Russell, Scott T. Misture, Theodore Besmann, Jake Amoroso, Kyle S. Brinkman
Summary: A series of Cr-substituted hollandite solid solution with a broad range of Cs content were investigated. Increasing Cs content induced a phase transition and improved thermodynamic stability. The study also found that the leaching performance of Cr hollandite samples was lower compared to other systems.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Chemistry, Physical
Philip M. Walker
Summary: This paper outlines the relationship between nuclear and atomic transitions and discusses examples of using external electromagnetic radiation to manipulate nuclear transitions associated with isomers.
RADIATION PHYSICS AND CHEMISTRY
(2022)
Article
Optics
Or Katz, Roy Shaham, Eran Reches, Alexey Gorshkov, Ofer Firstenberg
Summary: This article outlines and characterizes methods for mapping the state of photons onto collective states of noble-gas spins, which are long-lived but optically inaccessible. The mapping is achieved through coherent spin-exchange interaction arising from random collisions with alkali vapor.
Article
Physics, Multidisciplinary
Gian-Luca Schmid, Chun Tat Ngai, Maryse Ernzer, Manel Bosch Aguilera, Thomas M. Karg, Philipp Treutlein
Summary: By utilizing optical coherent feedback, nanomechanical membrane cooling was achieved remotely using atomic spins as a controller, leading to cooling the membrane to a very low temperature at room temperature. This method has the potential to cool the mechanical oscillator close to its quantum mechanical ground state and prepare nonclassical states.
Article
Physics, Applied
Kazuaki Hongu, Keisuke Fujii
Summary: We propose a simple and pure data-driven method to discover new energy levels of quantum many-body systems solely from observed line wavelengths. By computing all possible combinations from known energy levels and wavelengths of unidentified lines, the true levels can be reconstructed from multiple level-line combinations, while the wrong combinations are randomly distributed. This statistical method is demonstrated by finding new levels for various atomic and nuclear systems using available online unidentified line lists.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Physics, Multidisciplinary
Chi-Ming Chang, Sean Colin-Ellerin, Cheng Peng, Mukund Rangamani
Summary: In this paper, we present a one-parameter family of large N disordered models in three dimensions, with and without supersymmetry. These models interpolate between the critical large N vector model and a classical higher spin theory, as well as a theory with a classical string dual. We analyze the spectrum and operator product expansion data of these theories, and discuss the behavior of both supersymmetric and nonsupersymmetric models.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Grace M. Sommers, Benedikt Placke, Roderich Moessner, S. L. Sondhi
Summary: A system of hard spheres is controlled by density, with low density phase being liquid and high density phase being crystalline. Hard-core spin models, replacing translational degrees of freedom with orientational degrees of lattice spins, divide configurations into allowed and disallowed sectors. Varying exclusion and inclusion angles leads to Kosterlitz-Thouless phase transition between disordered and ordered phases with quasi-long-ranged order.
Article
Chemistry, Multidisciplinary
Harry S. Geddes, Henry D. Hutchinson, Alex R. Ha, Nicholas P. Funnell, Andrew L. Goodwin
Summary: By using the non-negative matrix factorisation (NMF) approach, the study demonstrates how the pair distribution function (PDF) of complex mixtures can be separated into contributions from individual phase components and interfaces between phases, focusing specifically on a model system Fe parallel to Fe3O4. The experimental results show excellent agreement with theoretical predictions, highlighting the significance of this method in characterising interfaces in complex functional materials.
Article
Materials Science, Ceramics
Rajesh Kumar, Amreen Jan, Mathieu Bauchy, N. M. Anoop Krishnan
Summary: Using molecular dynamics simulations, the study observed that irradiation increases disorder in short- and medium-range order in borosilicate glasses. The volumetric response of borosilicate glasses under irradiation shows a composition-dependent transition, with borate-rich compositions tending to swell and silica-rich glasses tending to densify. The increase in disorder in medium-range order plays a significant role in governing the volumetric changes in the irradiated structure.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2021)
Article
Physics, Applied
Pengcheng Fan, Heng Yuan, Lixia Xu, Jixing Zhang, Guodong Bian, Mingxin Li, Zhuo Wang
Summary: The adjusted Carr-Purcell-Meiboom-Gill sequence was used to detect C-13 nuclear spin signals coupled to a negatively-charged nitrogen-vacancy center in diamond, achieving high resolution detection. The improved frequency resolution and coherence dips width offer a promising approach to enhance the identification of nuclear spins in coupled electron-nuclear spin systems. The adjusted method can also be applied to other dynamical decoupling sequences for further improvement in spin detection.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Physics, Applied
Haochen Wang, Nicholas Adamski, Sai Mu, Chris G. van de Walle
Summary: This study provides a detailed analysis of the spontaneous and piezoelectric polarization behaviors of aluminum nitride alloy with Sc addition. It is found that the virtual crystal approximation produces accurate results for polarization but falls short in describing the phase stability of the alloy. Additionally, the internal-strain contribution dominantly enhances the piezoelectric properties induced by Sc, with the value of u increasing with scandium concentration, bringing the alloy closer to a layered hexagonal structure locally.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Applied
Joseph Casamento, Hyunjea Lee, Takuya Maeda, Ved Gund, Kazuki Nomoto, Len van Deurzen, Wesley Turner, Patrick Fay, Sai Mu, Chris G. van de Walle, Amit Lal, Huili (Grace) Xing, Debdeep Jena
Summary: Epitaxial ScxAl1-xN thin films grown on metal polar GaN substrates exhibit high relative dielectric permittivity, the largest among existing nitride materials. The films also have polarization discontinuity, which can be utilized for extending transistor operation in power electronics and high-speed microwave applications.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Xie Zhang, Mark E. Turiansky, Jimmy-Xuan Shen, Chris G. van de Walle
Summary: This Perspective critically discusses the defect tolerance in halide perovskites based on first-principles calculations. It shows that halide perovskites are not defect tolerant and suffer from defect-assisted nonradiative recombination, with comparable or higher nonradiative recombination rates than conventional semiconductors. The importance of accurate defect properties and defect engineering in improving the efficiency of perovskite solar cells is highlighted.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Physics, Applied
Joshua Leveillee, Samuel Ponce, Nicholas L. Adamski, Chris G. Van de Walle, Feliciano Giustino
Summary: The possibility of improving the hole mobility of GaN by epitaxial matching to ZnGeN2 and MgSiN2 is explored. Calculations show that lattice matching with these materials can lead to the inversion of certain hole bands and significantly increase hole mobility.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Sai Mu, Chris G. Van de Walle
Summary: This study uses density functional theory to assess the phase stability of monoclinic Ga2O3 and (AlxGa1-x)(2)O-3 alloys. It finds that the gamma and kappa phases of (AlxGa1-x)(2)O-3 have the lowest enthalpy of formation at 62.5% and 50% Al concentrations, respectively. At finite temperature, lattice vibrations tend to stabilize the kappa phase and destabilize the alpha and gamma phases, with the configurational entropy of the gamma phase playing a substantial role in stabilizing it.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Physics, Applied
Su-Hyun Yoo, Mira Todorova, Jorg Neugebauer, Chris G. Van de Walle
Summary: GaN/(Al, Ga)N heterojunctions are crucial for high-electron-mobility transistors. The density of the two-dimensional electron gas (2DEG) on the GaN side is significantly enhanced by the strong polarization fields at the interface. The source of the electrons in the 2DEG is intrinsic to the overall structure and the negative charge is balanced by fixed charge on the surface, rather than surface states.
PHYSICAL REVIEW APPLIED
(2023)
Article
Quantum Science & Technology
Mehmet T. Uysal, Mouktik Raha, Songtao Chen, Christopher M. Phenicie, Salim Ourari, Mengen Wang, Chris G. Van de Walle, Viatcheslav V. Dobrovitski, Jeff D. Thompson
Summary: In this work, coherent coupling between the electron spin of a single Er3+ ion and a single I = 1/2 nuclear spin in the solid-state host crystal, which is a fortuitously located proton (1H), is demonstrated. The nuclear spin is controlled using dynamical-decoupling sequences applied to the electron spin, allowing for one- and two-qubit gate operations. The longer coherence time of the nuclear spin, compared to the electron spin, is crucial for combining long-lived nuclear spin quantum registers with telecom-wavelength emitters for long-distance quantum repeaters.
Article
Physics, Multidisciplinary
Fangzhou Zhao, Mark E. Turiansky, Audrius Alkauskas, Chris G. Van de Walle
Summary: Trap-assisted Auger-Meitner recombination is highlighted as a dominant nonradiative process in wide-band-gap materials, and a first-principles methodology is presented to determine the rates of this process in semiconductors or insulators due to defects or impurities.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Ymir K. Frodason, Joel B. Varley, Klaus Magnus H. Johansen, Lasse Vines, Chris G. Van de Walle
Summary: Pathways and energy barriers for the migration of Ga vacancies (VGa) and Ga interstitials (Gai) in-Ga2O3 have been studied using hybrid functional calculations and the nudged elastic band method. A mechanism for the transformation of VGa between different split configurations has been described. The overall migration barriers for VGa and Gai in different crystal directions have been determined. The results provide insights into the thermally activated recovery processes in irradiated material.
Article
Materials Science, Multidisciplinary
Yubi Chen, Mark E. Turiansky, Chris G. Van de Walle
Summary: This study conducted comprehensive investigations on native point defects in beryllium oxide (BeO) using density functional theory. The stability and potential applications of different defects were analyzed, and suitable candidates for quantum defects were identified.
Article
Quantum Science & Technology
Raj N. Patel, David A. Hopper, Jordan A. Gusdorff, Mark E. Turiansky, Tzu-Yung Huang, Rebecca E. K. Fishman, Benjamin Porat, Chris G. Van de Walle, Lee C. Bassett
Summary: By using photon emission correlation spectroscopy, we revealed the optical dynamics of quantum emitters in hexagonal boron nitride. The experimental results showed the existence of quantum emitters with ideal single-photon emission and their photoluminescence emission lineshapes were consistent with individual vibronic transitions. However, polarization-resolved excitation and emission revealed the role of multiple optical transitions, and photon emission correlation spectroscopy revealed the complicated optical dynamics associated with excitation and relaxation.
Proceedings Paper
Engineering, Electrical & Electronic
Mengen Wang, Sai Mu, Chris G. Van de Walle
Summary: This paper discusses the diffusion behavior of dopants and point defects in monoclinic gallium oxide, as well as the diffusion of hydrogen in gallium oxide. The results provide important guidance for controlling doping in gallium oxide and its alloys.
OXIDE-BASED MATERIALS AND DEVICES XIII
(2022)
Article
Materials Science, Multidisciplinary
Sai Mu, Mengen Wang, Joel B. Varley, John L. Lyons, Darshana Wickramaratne, Chris G. Van de Walle
Summary: We used hybrid density functional calculations to analyze n-type doping in monoclinic (AlxGa1-x)(2)O-3 alloys. Our study focused on the impact of silicon, carbon, and hydrogen as impurities in metal-organic chemical vapor deposition (MOCVD) and their effect on the structural properties and charge-state transition levels of the alloys.
Article
Chemistry, Multidisciplinary
Xie Zhang, Mark E. Turiansky, Chris G. Van de Walle
Summary: Hybrid perovskites exhibit higher efficiencies than all-inorganic counterparts in photovoltaic applications, but organic cations can introduce more nonradiative recombination centers that affect performance. All-inorganic halide perovskites have better stability of the perovskite phase and hold promise for high-efficiency optoelectronic applications. These critical insights may prevent all-inorganic halide perovskites from being disregarded as potentially strong candidates for solar cell materials.
CELL REPORTS PHYSICAL SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Sai Mu, Andrew J. E. Rowberg, Joshua Leveillee, Feliciano Giustino, Chris G. Van de Walle
Summary: In this study, we investigated the conduction-band structure and electron mobility in rocksalt ScN using density functional theory. Our findings reveal a significant enhancement of electron mobility at high carrier concentrations. We also show how strain engineering can increase electron mobility, with different effects on (111) and (100) oriented ScN films.
Article
Chemistry, Physical
Sergey Yu. Ketkov, Sheng-Yuan Tzeng, Elena A. Rychagova, Anton N. Lukoyanov, Wen-Bih Tzeng
Summary: Metallocenes, including methylcobaltocene, play important roles in various fields of chemistry. The ionization energy and vibrational structure of (Cp ')(Cp)Co can be influenced by introducing methyl substituents. The mass-analyzed threshold ionization spectrum and DFT calculations provide accurate information about the properties and transformations of (Cp ')(Cp)Co.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Review
Chemistry, Physical
Qifeng Mu, Jian Hu
Summary: Polymer mechanochemistry has experienced a renaissance due to the rapid development of mechanophores and principles governing mechanochemical transduction or material strengthening. It has not only provided fundamental guidelines for converting mechanical energy into chemical output, but also found applications in engineering and smart devices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Da Hye Yang, Francesco Ricci, Fredrik L. Nordstrom, Na Li
Summary: Through systematic evaluation of the oiling-out behavior of procaine, we identified both stable and metastable liquid-liquid phase separation, and established phase diagrams to assist in rational selection of crystallization strategies.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Vikki Anand Varma, Simmie Jaglan, Mohd Yasir Khan, Sujin B. Babu
Summary: Designing engineering structures like nanocages, shells, and containers through self-assembly of colloids is a challenging problem. This work proposes a simple model for the subunit, which leads to the formation of monodispersed spherical cages or containers. The model with only one control parameter can be used to design cages with the desired radius.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Hainan Jiang, Yaolong He, Xiaolin Li, Zhiyao Jin, Huijie Yu, Dawei Li
Summary: The cycling lifespan and coulombic efficiency of lithium-ion batteries are crucial for high C-rate applications. The Li-ion concentration plays a crucial role in determining the mechanical integrity and structural stability of electrodes. This study focuses on graphite as the working electrode and establishes an experimental system to investigate the mechanical properties of composite graphite electrode at different C-rates. Considering the effect of Li-ion concentration in stress analysis is found to be significant.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Zhiye Wang, Yunchuan Li, Mingjun Sun
Summary: This study investigates the influence of intramolecular pi-pi interactions on the electronic transport capabilities of molecules. By designing and analyzing three pi-conjugated molecules, the researchers observe that different pi-conjugated structures have varying effects on electron transport. The findings provide a theoretical foundation for designing single-molecule electronic devices with multiple electron channels based on intramolecular pi-pi interactions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Yuandong Xu, Haoyang Feng, Chaoyang Dong, Yuqing Yang, Meng Zhou, Yajun Wei, Hui Guo, Yaqing Wei, Jishan Su, Yingying Ben, Xia Zhang
Summary: Hollow MoS2 cubes and spheres were successfully synthesized using a one-step hydrothermal method with the hard template method. The hollow MoS2 cubes exhibited higher specific capacitance and energy density compared to the hollow MoS2 spheres. The symmetrical supercapacitors assembled with these hollow structures showed good performance and high capacity retention after multiple cycles. These findings suggest that controlling the pore structure and surface characteristics of MoS2 is crucial for enhancing its electrochemical properties.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Ainhoa Oliden-Sanchez, Rebeca Sola-Llano, Joaquin Perez-Pariente, Luis Gomez-Hortiguela, Virginia Martinez-Martinez
Summary: The combination of photoactive molecules and inorganic structures is important for the development of advanced materials in optics. In this study, bulky dyes were successfully encapsulated in a zeolitic framework, resulting in emission throughout the visible spectrum.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Miaomiao Zhang, Cunyuan Pei, Qiqi Xiang, Lintao Liu, Zhongxu Dai, Huijuan Ma, Shibing Ni
Summary: The design of a solid electrolyte interphase (SEI) plays a crucial role in improving the electrochemical performance of anode materials. In this study, lithium difluoro(oxalate)borate (LiDFOB) is used as an electrolyte additive to form a protective SEI film on Li3VO4 (LVO) anodes. The addition of LiDFOB results in a dense, uniform, stable, and LiF-richer SEI, which enhances the Li-ion storage kinetics. The generated SEI also prevents further decomposition of the electrolyte and maintains the morphology of LVO anodes during charge/discharge processes. This work demonstrates the effectiveness of LiDFOB as a multi-functional additive for LiPF6 electrolytes and provides insights into SEI construction for high-performance LVO anodes.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
B. V. Andryushechkin, T. V. Pavlova, V. M. Shevlyuga
Summary: The atomic structure of the Ag(111)-p(4 x 4)-O phase was reexamined and two phases with the same periodicity were discovered. It was demonstrated that the accepted Ag6 model is incompatible with high-resolution oxygen-sensitive STM images.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
S. L. Romo-Avila, D. Marquez-Ruiz, R. A. Guirado-Lopez
Summary: In this study, we used density functional theory (DFT) calculations to investigate the interaction between model graphene oxide (GO) nanostructures and chlorine monoxide ClO. We aimed to understand the role of this highly oxidizing species in breaking C-C bonds and forming significant holes on GO sheets. Our results showed that C-C bonds in a single graphene oxide sheet can be broken through a simple mechanism involving the dissociation of two chemically attached ClO molecules. The formation of carbonyl groups and holes on the GO surface was also observed. This study provides important insights into the degradation of carbon nanotubes and the stability of GO during the myeloperoxidase (MPO) catalytic cycle.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Alberto Garcia-Fernandez, Birgit Kammlander, Stefania Riva, Hakan Rensmo, Ute B. Cappel
Summary: In this study, the X-ray stability of five different lead halide perovskite compositions (MAPbI3, MAPbCl3, MAPbBr3, FAPbBr3, CsPbBr3) was investigated using photoelectron spectroscopy. Different degradation mechanisms and resistance to X-ray were observed depending on the crystal composition. Overall, perovskite compositions based on the MA+ cation were found to be less stable than those based on FA+ or Cs+. Metallic lead formation was most easily observed in the chloride perovskite, followed by bromide, and very little in MAPbI3. Multiple degradation processes were identified for the bromide compositions, including ion migration, formation of volatile and solid products, as well as metallic lead. CsBr was formed as a solid degradation product on the surface of CsPbBr3.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Timofei Rostilov, Vadim Ziborov, Alexander Dolgoborodov, Mikhail Kuskov
Summary: The shock-loading behavior of nanomaterials is investigated in this study. It is found that shock compaction waves exhibit a distinct two-step structure, with the formation of faster precursor waves that travel ahead of the main compaction waves. The complexity of the shock Hugoniot curve of the tested nanomaterial is described, and the effect of initial porosity on the compressed states is demonstrated.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Sergey S. Nikitin, Alexander D. Koryakov, Elizaveta A. Antipinskaya, Alexey A. Markov, Mikhail V. Patrakeev
Summary: The stability of La1/3Sr2/3Fe1-xMnxO3-delta, a perovskite-type oxide, under reducing conditions is dependent on the manganese content. Increasing the manganese content leads to a decrease in stability. The behavior of iron and manganese in the oxide shows distinct differences, which can be attributed to the difference in the enthalpy of oxidation reactions. Additionally, the change in the La/Sr ratio affects the concentration of iron and manganese ions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)
Article
Chemistry, Physical
Mosayeb Naseri, Shirin Amirian, Mehrdad Faraji, Mohammad Abdur Rashid, Maicon Pierre Lourenco, Venkataraman Thangadurai, D. R. Salahub
Summary: Inspired by the successful transfer of freestanding ultrathin films of SrTiO3 and BiFeO3, this study assessed the structural stability and investigated the electronic, optical, and thermoelectric properties of a group of two-dimensional perovskite-type materials called perovskenes. The findings revealed that these materials are wide bandgap semiconductors with potential application in UV shielding. Moreover, they exhibit better electrical and thermal conductivity at high temperatures, enabling efficient power generation in thermoelectric devices.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2024)