MRSEC Research Data

Persistent link for this collectionhttps://hdl.handle.net/11299/214081

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Chemical bonding and Born charge in 1T-HfS2
(2021-04-09) Neal, Sabine N; Li, Shutong; Birol, Turan; Musfeldt, Janice L; li000269@umn.edu; Li, Shutong
We combine infrared absorption and Raman scattering spectroscopies to explore the properties of 1T-HfS2- a heavy transition metal chalcogenide with strong spin-orbit coupling due to incorporation of the 5d center. We employ the LO-TO splitting of the Eu mode along with a reevaluation of mode mass, unit cell volume, and dielectric constant to reveal the Born effective charge. We find ZB*= 5.33e, in excellent agreement with complementary first principles calculations. In addition to resolving controversy over the nature of chemical bonding in this system, we decompose the Born charge into polarizability and local (ionic) charge. We find α= 5.07 Å3 and Z*= 5.19e, respectively. In order to understand how ZB* relates to the nominal 4+ charge of the Hf center, we decompose the theoretical Born effective charge into band-by-band contributions, and find that polar displacement-induced charge transfer from sulfur p to hafnium d orbitals is responsible for the enhancement of Born charge. 1T-HfS2 is thus an ionic crystal with strong and dynamic covalent effects.
Data files of work on LaCoO3 using VASP
(2020-08-05) Paul, Arpita; Birol, Turan; paula@umn.edu; Paul, Arpita; Birol Research Group
Sample VASP input file used to study LaCoO3 (INCAR) Band structures of LaCoO3 at each values of strain (used to determine carrier effective mass) Wannier functions derived from e_g orbitals of LaCoO3 (used to determine splitting between dx2-y2 and dz2 orbitals)
Data for "Identifying a critical micelle temperature in simulations of disordered asymmetric diblock copolymer melts"
(2021-10-18) Chawla, Anshul; Bates, Frank S; Dorfman, Kevin D; Morse, David C; chawl029@umn.edu; Chawla, Anshul; University of Minnesota
We have used coarse-grained molecular dynamics simulations to identify a critical micelle temperature in a diblock copolymer melt by analyzing the appearance of micelles. The files contain the data and an example simulation file which can be used with Hoomd-blue version 2.9.0. The data has been published as "Identifying a critical micelle temperature in simulations of disordered asymmetric diblock copolymer melts" in Physical Review Materials.
Data for "Scattering mechanisms and mobility enhancement in epitaxial BaSnO3thin films probed via electrolyte gating"
(2020-08-05) Wang, Helin; Prakash, Abhinav; Reich, Konstantin; Ganguly, Koustav; Leighton, Chris; leighton@umn.edu; Leighton, Chris; Leighton Electronic and Magnetism Lab
Data includes temperature-dependent electronic transport (sheet resistance, electron density, and mobility) of ion-gel-gated BaSnO3 thin films of various thicknesses and growth methods. The mobility vs electron density experimental data and the fitting results (fits) are also provided.
Data for "Stability of Cubic Single Network Phases in Diblock Copolymer Melts"
(2022-07-25) Chen, Pengyu; Mahanthappa, Mahesh K; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Research Group
This dataset contains the self-consistent field theory (SCFT) simulation results and data for geometric analysis in "Stability of cubic single networks in diblock copolymer melts" by Chen et. al. (DOI: 10.1002/pol.20220318). SCFT was used to investigate the stability of cubic single and double network phases. Geometric analysis, including the calculations of mean curvatures and interfacial areas per unit volume of the domain interface, was used to understand the metastability of the single network phases. With this dataset, users should be able to regenerate the calculations and figures that appeared in the paper.
Data for "Stability of the Double Gyroid Phase in Bottlebrush Diblock Copolymer Melts"
(2021-10-04) Park, So Jung; Cheong, Guo Kang; Bates, Frank S; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Research Group
This data set contains the input and output data files used for the self-consistent field theory simulations in "Stability of the double gyroid phase in bottlebrush diblock copolymer melts" by Park et al. Self-consistent field theory was used to study the self-assembly of bottlebrush block copolymers, focusing on the effect of the bottlebrush architecture on the stability of the double gyroid phase.
Data for Alternating Gyroid in Block Polymer Blends
(2022-04-27) Park, Sojung; Bates, Frank S; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Research Group - University of Minnesota Department of Chemical Engineering and Materials Science
This data set contains the input and output files from the PSCF C++ program used for the self-consistent field theory (SCFT) simulation in "Alternating gyroid in block polymer blends" by Park et al. (doi/10.1021/acsmacrolett.2c00115). Self-consistent field theory was used to investigate the stability of alternating gyroid phase in the ternary AB/BC/ABC block polymer mixture. With this dataset, users should be able to regenerate all the calculations that appeared in the paper, using the open-source C++ SCFT program.
Data for Alternating Gyroid Stabilized by Surfactant-like Triblock Terpolymers in IS/SO/ISO Ternary Blends
(2023-03-22) Chen, Pengyu; Bates, Frank S; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin, D; Dorfman Research Group - University of Minnesota Department of Chemical Engineering and Materials Science
This dataset contains the self-consistent field theory (SCFT) simulation results in the associated paper (https://doi.org/10.1021/acs.macromol.2c02485)
Data for Boundary Frustration in Double-Gyroid Thin Films
(2024-02-29) Magruder, Benjamin R; Morse, David C; Ellison, Christopher J; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Group, UMN CEMS
We have used self-consistent field theory to predict the morphology and preferred orientation of the double-gyroid phase in thin films of AB diblock polymers. A manuscript has been submitted containing this data, and is expected to appear shortly. The data were generated using the C++ version of the open-source software PSCF (https://pscf.cems.umn.edu/). All input and output files from PSCF used to generate the data in the paper are included in this dataset, as well as the code used to process the data and generate the figures.
Data for Chain and Structural Dynamics in Melts of Sphere-Forming Diblock Copolymers
(2024-07-22) Chawla, Anshul; Bates, Frank S; Dorfman, Kevin D; Morse, David C; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Research Group
Processed simulation data appearing in the related manuscript
Data for Combining photocontrolled-cationic and anionic-group transfer polymerizations using a universal mediator: enabling access to two- and three-Mechanism block copolymers
(2024-08-15) Hosford, Brandon M; Ramos, William; Lamb, Jessica R; jrlamb@umn.edu; Lamb, Jessica R; Lamb Research Group
An ongoing challenge in polymer chemistry is accessing diverse block copolymers from multiple polymerization mechanisms and monomer classes. One strategy to accomplish this goal without intermediate compatibilization steps is the use of universal mediators. Thiocarbonyl thio (TCT) functional groups are well-known mediators to combine radical with either cationic or anionic polymerization, but a sequential cationic-anionic universal mediator system has never been reported. Herein, we report a TCT universal mediator that can sequentially perform photocontrolled cationic polymerization and thioacyl anionic group transfer polymerization to access poly(ethyl vinyl ether)-block-poly(thiirane) polymers for the first time. Thermal analyses of these block copolymers provide evidence of microphase separation. The success of this system, along with the established compatibility of radical polymerization, enabled us to further chain extend the cationic-anionic diblock using radical polymerization of N-isopropylacrylamide. The resulting terpolymer represents the first example of a triblock made from three different monomer classes incorporated via three different mechanisms without any end-group modification steps. The development of this simple, sequential synthesis using a universal mediator approach opens up new possibilities by providing facile access to diverse block copolymers of vinyl ethers, thiiranes, and acrylamides.
Data for Crystal-Chemical Origins of the Ultrahigh Conductivity of Metallic Delafossites
(2023-11-09) Zhang, Yi; Tutt, Fred; Evans, Guy N; Sharma, Prachi; Haugstad, Greg; Kaiser, Ben; Ramberger, Justin; Bayliff, Samuel; Tao, Yu; Manno, Mike; Garcia-Barriocanal, Javier; Chaturvedi, Vipul; Fernandes, Rafael M; Birol, Turan; Seyfried Jr, William E; Leighton, Chris; leighton@umn.edu; Leighton, Chris; Leighton Electronic and Magnetic Materials Lab
Despite their highly anisotropic complex-oxidic nature, certain delafossite compounds (e.g., PdCoO2, PtCoO2) are the most conductive oxides known, for reasons that remain poorly understood. Their room-temperature conductivity can exceed that of Au, while their low-temperature electronic mean-free-paths reach an astonishing 20 um. It is widely accepted that these materials must be ultrapure to achieve this, although the methods for their growth (which produce only small crystals) are not typically capable of such. Here, we first report a new approach to PdCoO2 crystal growth, using chemical vapor transport methods to achieve order-of-magnitude gains in size, the highest structural qualities yet reported, and record residual resistivity ratios (>440). Nevertheless, the first detailed mass spectrometry measurements on these materials reveal that they are not ultrapure, typically harboring 100s-of-parts-per-million impurity levels. Through quantitative crystal-chemical analyses, we resolve this apparent dichotomy, showing that the vast majority of impurities are forced to reside in the Co-O octahedral layers, leaving the conductive Pd sheets highly pure (~1 ppm impurity concentrations). These purities are shown to be in quantitative agreement with measured residual resistivities. We thus conclude that a previously unconsidered “sublattice purification” mechanism is essential to the ultrahigh low-temperature conductivity and mean-free-path of metallic delafossites. This dataset contains all digital data in the published paper of the same name.
Data for Doping- and Strain-Dependent Electrolyte-Gate-Induced Perovskite to Brownmillerite Transformation in Epitaxial La1−xSrxCoO3−δ Films
(2021-11-17) Chaturvedi, Vipul; Postiglione, William M; Chakraborty, Rohan D; Yu, Biqiong; Tabiś, Wojciech; Hameed, Sajna; Biniskos, Nikolaos; Jacobson, Andrew; Zhang, Zhan; Zhou, Hua; Greven, Martin; Ferry, Vivian E; Leighton, Chris; leighton@umn.edu; Leighton, Chris; Chemical Engineering and Materials Science, University of Minnesota; AGH University of Science and Technology, Faculty of Physics and Applied Computer Science; Advanced Photon Source, Argonne National Laboratory; School of Physics and Astronomy, University of Minnesota
Electrolyte-gate-induced perovskite to brownmillerite transformations in La1-xSrxCoO3-d (LSCO) has been shown to be a facile technique to toggle between disparate electronic and magnetic phases in a single perovskite oxide thin film. Here we study the doping (Sr concentration), and strain (epitaxially imparted from the substrate) dependence of this topotactic transformation in LSCO thin films across almost the entire phase diagram. This repository page serves as a place to store the Figure plots and raw data from the cited publication.
Data for Equilibrium Phase Behavior of Gyroid-Forming Diblock Polymer Thin Films
(2024-08-08) Magruder, Benjamin; Ellison, Christopher; Dorfman, Kevin; dorfman@umn.edu; Dorfman, Kevin; Dorfman Research Group
The dataset contains the results of thin-film self-consistent field theory calculations for the double-gyroid phase and other related phases in AB diblock polymers. All results used to construct the figures in the referenced manuscript are included in this dataset, along with many of the scripts used to perform the analysis in the manuscript. To reduce the size of the dataset, we opted to include only the first and last field file in each parameter sweep, though we kept the corresponding summary file at every state point in every sweep, and included all necessary input files to regenerate the data if desired. The PSCF software package (C++ version) was used to generate this dataset (https://github.com/dmorse/pscfpp).
Data for Gaming self-consistent field theory: Generative block polymer phase discovery
(2023-10-18) Chen, Pengyu; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Research Group - University of Minnesota Department of Chemical Engineering and Materials Science
This dataset contains the input and output files for self-consistent field theory (SCFT) simulations and the training of generative adversarial networks (GANs) in the associated paper.
Data for Magnetization dynamics in synthetic antiferromagnets with perpendicular magnetic anisotropy
(2023-11-09) Huang, Dingbin; Zhang, Delin; Kim, Yun; Wang, Jian-Ping; Wang, Xiaojia; wang4940@umn.edu; Wang, Xiaojia; Materials Research Science & Engineering Center
This repository contains data along with associated output from instrumentation supporting all results reported in Huang, D.; Zhang, D.; Kim, Y; Wang, J.P.; and Wang X. Magnetization dynamics in synthetic antiferromagnets with perpendicular magnetic anisotropy. Phys. Rev. B., 2023, 107, 214438. The magnetization dynamics of the perpendicular synthetic antiferromagnets (p-SAFs) sample is detected by time-resolved magneto-optical Kerr effect (TR-MOKE), which is ultrafast-laser-based metrology utilizing a pump-probe configuration. In TR-MOKE, pump laser pulses interact with the sample, initiating magnetization dynamics in magnetic layers via inducing ultrafast thermal demagnetization. The laser-induced heating brings a rapid decrease to the magnetic anisotropy fields and interlayer exchange coupling (IEC), which changes equilibrium direction of magnetization in each layer and initiates the precession. The magnetization dynamics due to pump excitation is detected by a probe beam through MOKE. In our setup, the incident probe beam is normal to the sample surface (polar MOKE); therefore, the Kerr rotation angle (θ_K) of the reflected probe beam is proportional to the z component of the magnetization.
Data for Room-Temperature Valence Transition in a Strain-Tuned Perovskite Oxide
(2022-11-09) Chaturvedi, Vipul; Ghosh, Supriya; Gautreau, Dominique; Postiglione, William M; Dewey, John E; Quarterman, Patrick; Balakrishnan, Purnima P; Kirby, Brian J; Zhou, Hua; Cheng, Huikai; Huon, Amanda; Fitzsimmons, Michael R; Korostynski, Caroline; Jacobson, Andrew; Figari, Lucca; Barriocanal, Javier G; Birol, Turan; Mkhoyan, K Andre; Leighton, Chris; leighton@umn.edu; Leighton, Chris; Leighton Electronic and Magnetic Materials Lab
Cobalt oxides have long been understood to display intriguing phenomena known as spin-state crossovers, where the cobalt ion spin changes vs. temperature, pressure, etc. A very different situation was recently uncovered in praseodymium-containing cobalt oxides, where a first-order coupled spin-state/structural/metal-insulator transition occurs, driven by a remarkable praseodymium valence transition. Such valence transitions, particularly when triggering spin-state and metal-insulator transitions, offer highly appealing functionality, but have thus far been confined to cryogenic temperatures in bulk materials (e.g., 90 K in Pr1-xCaxCoO3). Here, we show that in thin films of the complex perovskite (Pr1-yYy)1-xCaxCoO3-delta, heteroepitaxial strain tuning enables stabilization of valence-driven spin-state/structural/metal-insulator transitions to at least 291 K, i.e., around room temperature. This dataset contains all digital data published in the Nature Communications paper of the same name.
Data for Simulations of sphere-forming diblock copolymer melts
(2022-09-15) Chawla, Anshul; Bates, Frank S; Dorfman, Kevin D; Morse, David C; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Research Group
Processed simulation data appearing in the related manuscript.
Data for Single Gyroid in H-shaped Block Copolymers
(2023-10-05) Park, Sojung; Bates, Frank S; Dorfman, Kevin D; dorfman@umn.edu; Dorfman, Kevin D; Dorfman Research Group - University of Minnesota Department of Chemical Engineering and Materials Science
This data set contains the input and output files from the PSCF C++ program used for the self-consistent field theory (SCFT) simulation in "Single Gyroid in H-shaped Block Copolymers." Self-consistent field theory was used to investigate the equilibrium phase behavior of H-shaped block copolymers. With this dataset, users should be able to regenerate all the calculations that appeared in the paper, using the open-source C++ SCFT program available on GitHub (https://github.com/dmorse/pscfpp).
Data for Surface Relief Terraces in Double Gyroid-Forming Polystyrene-block-Polylactide Thin Films
(2023-09-28) Yang, Szu-Ming; Oh, Jinwoo; Magruder, Benjamin R; Kim, HeeJoong; Dorfman, Kevin D; Mahanthappa, Mahesh K; Ellison, Christopher J; cellison@umn.edu; Ellison, Christopher J; University of Minnesota Department of Chemical Engineering and Materials Science
This study describes the thin film self-assembly behavior of a polystyrene-block-polylactide (SL-G) diblock copolymer, which undergoes melt self-assembly in bulk into a double gyroid (DG) network phase with a cubic unit cell parameter a = 52.7 nm. Scanning electron microscopy (SEM) and grazing-incidence small-angle X-ray scattering (GISAXS) reveal that thermally annealing 140–198 nm thick copolymer films on SiO2 substrates below the morphological order-to-disorder transition temperature yields polydomain DG structures, in which the (422) planes are oriented parallel to the surface. Bright-field optical microscopy (OM) and atomic force microscopy (AFM) analyses further reveal the film thickness-dependent formation of topographical terraces, including islands, holes, and bicontinuous features. The occurrence of these features sensitively depends on the incommensurability of the as-prepared film thickness and the (211)-interplanar spacing (d211) of the DG unit cell. While the steps heights between adjacent terraces exhibiting characteristic “double wave” patterns of the DG (422) planes coincide with d211, previously unreported transition zones between adjacent terraces are observed wherein “boomerang” and “droplet” patterns are observed. These intermediate patterns follow the expected sequence of adjacent termination planes of the bulk DG unit cell along the [211] direction, as confirmed by comparisons with self-consistent mean-field theory calculations.

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