Article
Chemistry, Multidisciplinary
Yarden Mazal Jahn, Assaf Ya'akobovitz
Summary: The research found that HfS2 and HfSe2 exhibit excellent elastic properties and stretchability, making them suitable for flexible electronic and optoelectronic applications. Additionally, a relatively simple laser oxidation treatment can significantly increase the Young's moduli of the oxidized layers.
Article
Materials Science, Multidisciplinary
Ryan A. Kowalski, Joshua Ryan Nolen, Georgios Varnavides, Sebastian Mika Silva, Jack E. Allen, Christopher J. Ciccarino, Dominik M. Juraschek, Stephanie Law, Prineha Narang, Joshua D. Caldwell
Summary: This study reports the exceptionally broad Reststrahlen bands of two Hf-based transition metal dichalcogenides (TMDs) that can support surface phonon polaritons (SPhPs) within the mid-infrared (mid-IR) into the terahertz (THz) range. The infrared transmission and reflectance spectra of hafnium disulfide (HfS2) and hafnium diselenide (HfSe2) flakes were measured, and their dielectric functions were extracted. The results show that these Hf-based TMDs have significantly broader Reststrahlen bands compared to other commonly explored TMDs, making them promising materials for nanophotonics and sensing applications in the mid- to far-infrared range.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Chemistry, Physical
Jinlin Bao, Lu Yang, Guili Liu, Yan Wang, Tao Liu
Summary: In this study, we calculated the phonon spectra of HfS2, HfSe2, and HfS2/HfSe2 heterojunction under biaxial tensile strain and analyzed the effect of strain on the stability of the structures using density functional perturbation theory (DFPT). The results showed that monolayer HfS2 and HfSe2 can withstand high strains, while the HfS2/HfSe2 heterostructure has a lower limit. The van der Waals forces between the layers have little effect on the in-plane behavior but can cause phonon splitting in the vertical direction. Additionally, biaxial strain affects the entropy, enthalpy, and free energy of the systems but has little impact on the heat capacity at high temperatures.
Article
Chemistry, Physical
Muhammad Waqas Qureshi, M. A. Ali, Xinxin Ma, Guangze Tang, M. Usman Javed, Durga Paudyal
Summary: This study investigates the thermodynamic and phonon stabilities, as well as the elastic properties, of newly synthesized Ti2ZnX phases. The results show that Ti2ZnN has less anisotropic elastic properties compared to Ti2ZnC. The study also analyzes the surface properties of Ti2ZnX and confirms the presence of strong covalent bonding between Ti-X and Ti-Zn atoms.
SURFACES AND INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
N. Siminel, K. Sushkevich, S. Aazou, A. Micu, A. Siminel, Z. Sekkat, L. Kulyuk
Summary: The temperature dependence of the luminescence spectra of MoSe2 crystals intercalated with I2 molecules has been investigated. The luminescence spectrum consists of a zero-phonon doublet and its phonon replicas, caused by the recombination of excitons bound on iodine molecules embedded in the van der Waals gap. The rate of radiative recombination of the B state is found to be 76 times higher than the A state.
OPTICAL MATERIALS EXPRESS
(2023)
Article
Materials Science, Multidisciplinary
S. Rahman, Linyan Wang, H. Saqib, D. Errandonea, Li Yang, Yongsheng Zhao, Yukai Zhuang, Guoying Gao, Lin Wang, Yongjun Tian
Summary: The application of high pressure accelerates the understanding of structure and exotic electronic states in transition metal dichalcogenides, leading to the discovery of intriguing phenomena. HfS2 exhibits tunable electronic properties under pressure, with a gradual narrowing of band-gap below 40 GPa, pressure-induced metallization above 40 GPa, and superconductivity starting around 115 GPa. The high Tc superconductivity induced by pressure is closely related to structural reconstructions and changes in electronic states near the Fermi surface.
MATERIALS TODAY PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Ramesh Paudel, Jing-Chuan Zhu, Moaid K. Hussain, Mohammed Batouche, Muhammad Waqas Qureshi, Durga Paudyal
Summary: The study utilized density functional theory calculations to investigate the structural stability, electronic structure, and magnetic and optical properties of CoMnZnSi quaternary Heusler alloy in different forms. The results indicate excellent half-metallic properties and suitability for spintronic applications.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Physics, Applied
Yimin Sun
Summary: The optoelectronic properties of monolayer HfS2, HfSe2, and HfS2/HfSe2 heterostructures under biaxial strain were calculated using density functional perturbation theory (DFPT). The heterostructure formed by monolayer HfS2 and HfSe2 undergoes a transition from an indirect to a direct bandgap, with the bandgaps of all systems experiencing a linear increase under biaxial tensile strain. The stability of the structures was confirmed by calculating the phonon spectra. The van der Waals interactions between the layers of the heterostructure had minimal influence in the x-y plane, but could induce interlayer tearing in the vertical direction, resulting in earlier loss of stability compared to the monolayer structures. The optical absorption and reflectance properties of the three systems under strain were also calculated, and the two-dimensional heterostructure exhibited significantly improved absorption coefficients and reflectance in the high-energy region compared to the two monolayer structures.
MODERN PHYSICS LETTERS B
(2023)
Article
Materials Science, Multidisciplinary
E. G. Shkvarina, A. I. Merentsov, M. S. Postnikov, A. S. Shkvarin, S. V. Pryanichnikov, I. Pis, S. Nappini, F. Bondino, A. N. Titov
Summary: The study found that intercalating Cu into TiSe2 leads to the displacement of Ni atoms, due to charge transfer from Cu to TiSe2. The hybridization between Ni 3d and Se 4p, 4s states is stronger than that between Ni 3d and Ti 3d.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Arihant Bhandari, Prashant Kumar Gupta, Jishnu Bhattacharya, Raj Ganesh S. Pala
Summary: We demonstrate a correlation between the stabilization of different material polymorphs and their utility. By using a structural naming system, we can evaluate and compare the native and nonnative polymorphs. Our analysis shows that nonnative phases have higher surface stability than the corresponding native phases, suggesting a preference for stabilizing nonnative phases at the nanoscale. These findings can assist in engineering the properties of material-centric devices.
Article
Materials Science, Multidisciplinary
S. Rahman, H. Saqib, X. Liang, D. Errandonea, A. S. Resta, A. Molina-Sanchez, G. Gao, L. Wang, Y. Tian, H-k. Mao
Summary: The two-dimensional semiconductor 1T-HfSe2 exhibits highly tunable transport properties under pressure, including metallization and pressure-driven superconductivity. The study suggests the presence of a charge-density wave (CDW) state at low pressures, which is suppressed under high pressures. The occurrence of metallization and superconducting transition is attributed to a structural phase transition and changes in band structure.
MATERIALS TODAY PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Swagata Acharya, Dimitar Pashov, Mark van Schilfgaarde
Summary: By employing an advanced ab initio Green's function description, this study shows that the superconductivity in FeSe is not significantly affected by its nematic phase, suggesting that nematicity is not the primary force driving superconducting pairing in this material.
Article
Physics, Condensed Matter
Igor Antoniazzi, Natalia Zawadzka, Magdalena Grzeszczyk, Tomasz Wozniak, Jordi Ibanez, Zahir Muhammad, Weisheng Zhao, Maciej R. Molas, Adam Babinski
Summary: The temperature dependence of Raman scattering (RS) in bulk hafnium disulfide (HfS2) is investigated, revealing unexpected energy shifts of the main Raman-active modes at different temperatures, as well as the emergence of a new mode. The optical anisotropy of RS in HfS2 is highly dependent on the excitation energy, and the presence of iodine molecules intercalated in the van der Waals gaps between HfS2 layers is also analyzed for possible effects. The results are discussed in the context of resonant light-phonon interactions.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Energy & Fuels
Yee H. Robin Chang, Tiem L. Yoon, Keat H. Yeoh, Thong L. Lim
Summary: The study explores the optimization of thermoelectric performances of stable Cm-SnSSe and P3m1-SnSeS phases, which exhibit low thermal conductivity and satisfactory thermoelectric performances beyond 400 K. Hole doping at 10(20) cm(-3) concentration leads to improved ZT values and broad temperature plateau, showing potential for industrial waste heat management.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Chemistry, Physical
K. Idczak, E. Wachowicz
Summary: This study demonstrates that intercalated gadolinium atoms can significantly affect the electronic properties of graphene and the buffer layer, and temperature-induced intercalation can cause the buffer layer to decouple and transform into a new graphene layer.
APPLIED SURFACE SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Vitaliy Romaka, Ahmad Omar, Wolfgang Loeser, Bernd Buechner, Sabine Wurmehl
Summary: Investigations into the thermodynamic phase diagram of Co-based Heusler phases, focusing on the quaternary region of CoCrCoAl-CoFe, revealed critical points and immiscibility regions through DFT and thermodynamic calculations, offering valuable insights for materials design.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Olga Kataeva, Kamil Ivshin, Kirill Metlushka, Kristina Nikitina, Vera Khrizanforova, Yulia Budnikova, Robert R. Fayzullin, Shamil Latypov, Sandra Schiemenz, Michael Bretschneider, Alexey Popov, Stanislav Avdoshenko, Yulia Krupskaya, Bernd Buchner, Martin Knupfer
Summary: A series of new charge-transfer cocrystals of F(2)TCNQ with anthracene, tetracene, and chrysene were prepared and characterized. The study revealed that face-to-face pi-pi interactions are crucial for the formation of cocrystals, but lateral noncovalent interactions also play a significant role in the supramolecular arrangement and charge transfer. UV/vis spectroscopy and electronic structure quantum chemical calculations classified these cocrystals as small-gap semiconductors with energy gaps of 0.7-1.3 eV.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Nanoscience & Nanotechnology
Daniel Wolf, Sebastian Schneider, Ulrich K. Rossler, Andras Kovacs, Marcus Schmidt, Rafal E. Dunin-Borkowski, Bernd Buechner, Bernd Rellinghaus, Axel Lubk
Summary: Holographic vector-field electron tomography quantitatively reconstructed the three-dimensional magnetic texture of Bloch skyrmion tubes in FeGe with sub-10-nanometre resolution, revealing complex three-dimensional modulations and fundamental principles of skyrmion formation.
NATURE NANOTECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
Rui Lou, Alexander Fedorov, Qiangwei Yin, Andrii Kuibarov, Zhijun Tu, Chunsheng Gong, Eike F. Schwier, Bernd Buechner, Hechang Lei, Sergey Borisenko
Summary: The entanglement of charge density wave (CDW), superconductivity, and topologically nontrivial electronic structure has been discovered in the kagome metal AV3Sb5 (A = K, Rb, Cs) family recently. Using high-resolution angle-resolved photoemission spectroscopy, the electronic properties of CDW and superconductivity in CsV3Sb5 are studied. The spectra around K over line exhibit a peak-dip-hump structure associated with two separate branches of dispersion, indicating the isotropic CDW gap opening below EF. The presence of a superconducting gap on both the electron band around Gamma over line and the flat band around K suggests multiband superconductivity. Our results shed light on the controversial origin of the CDW and provide insights into the relationship between CDW and superconductivity.
PHYSICAL REVIEW LETTERS
(2022)
Article
Chemistry, Physical
Lorenzo Francesco Madeo, Patrizia Sarogni, Giuseppe Cirillo, Orazio Vittorio, Valerio Voliani, Manuela Curcio, Tyler Shai-Hee, Bernd Buechner, Michael Mertig, Silke Hampel
Summary: A hybrid hydrogel was developed by loading curcumin onto graphene oxide nanosheets and blending them into an alginate hydrogel. The resulting system showed improved stability and exhibited strong anticancer effects.
Article
Materials Science, Multidisciplinary
T. Klaproth, E. Mueller, C. Habenicht, B. Buechner, M. Knupfer, M. Roslova, A. Isaeva, T. Doert, A. Koitzsch
Summary: Transition metal trichlorides exhibit peculiar and versatile magnetic properties. This study reveals that transition metal substitution can modify the optical properties of the host without compromising its electronic structure. The findings highlight the potential of material engineering in trichlorides.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Chemistry, Physical
Felix Talnack, Sebastian Hutsch, Michael Bretschneider, Yulia Krupskaya, Bernd Buechner, Marc Malfois, Mike Hambsch, Frank Ortmann, Stefan C. B. Mannsfeld
Summary: Polymorphism refers to the ability of many organic molecules to adopt different crystal structures without changing their chemical structure. It has been found to have an impact on the solid-state properties of organic materials, such as charge transport in organic semiconductors. In this study, a new polymorphic crystal structure of the p-type small molecule semiconductor C10-DNTT is presented. The transition between different crystal structures was observed during heating, and the thin-film crystal structure of both polymorphs was refined using optical microscopy and X-ray scattering measurements. The thermal expansion and anisotropic molecular interactions were further analyzed using density-functional theory calculations.
MOLECULAR SYSTEMS DESIGN & ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Felix Hansen, Rico Fucke, Titouan Charvin, Samuel Froeschke, Daniel Wolf, Romain Giraud, Joseph Dufouleur, Nico Graessler, Bernd Buechner, Peer Schmidt, Silke Hampel
Summary: This study proposes a method for the synthesis of mixed crystals of bismuth and antimony tellurides, which belong to the V2VI3 material family. The ideal synthesis conditions were determined through thermodynamic calculations and optimization experiments. The synthesized nanosheets exhibit high crystallinity and quality, with a significantly reduced carrier density compared to the binary compounds.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Chemistry, Multidisciplinary
Bertold Rasche, Julius Brunner, Tim Schramm, Madhav Prasad Ghimire, Ulrike Nitzsche, Bernd Buchner, Romain Giraud, Manuel Richter, Joseph Dufouleur
Summary: This paper presents a method using atomic force microscopy to measure the cleavage energy of van der Waals materials and quasi-two-dimensional materials. The method is validated through experiments and can be used as a tool for manipulating exfoliated flakes, offering a new route for the fabrication of nanostructures.
Article
Physics, Multidisciplinary
Seung-Ho Baek, Yeahan Sur, Kee Hoon Kim, Matthias Vojta, Bernd Buechner
Summary: Single crystals of pristine and 6% Pd-intercalated 2H-TaSe2 were studied using Se-77 nuclear magnetic resonance. The Se-77 spectrum showed line narrowing upon Pd intercalation, indicating the presence of correlated local lattice distortions above the charge density wave (CDW) transition temperature. The Knight shift data suggested a partial Fermi surface gap opening in the incommensurate CDW transition. The spin dynamics study revealed a pseudogap behavior dominating the low-energy spin excitations, which gets stronger along with superconductivity in the Pd-6% sample.
NEW JOURNAL OF PHYSICS
(2022)
Article
Multidisciplinary Sciences
Shu-Jen Wang, Michel Panhans, Ilia Lashkov, Hans Kleemann, Federico Caglieris, David Becker-Koch, Joern Vahland, Erjuan Guo, Shiyu Huang, Yulia Krupskaya, Yana Vaynzof, Bernd Buechner, Frank Ortmann, Karl Leo
Summary: The charge and thermoelectric transport in modulation-doped large-area rubrene thin-film crystals with different crystal phases were investigated. The results showed that modulation doping, together with high-mobility crystalline organic semiconductor films, is a previously unexplored strategy for achieving high-performance organic thermoelectrics. Theoretical studies provided insight into the energy landscape of the heterostructures and its influence on qualitative trends of the Seebeck coefficient.
Article
Materials Science, Multidisciplinary
Jochen Simon, Axel Herguth, Leah Kutschera, Giso Hahn
Summary: Hydrogen-rich crystalline silicon samples are produced by introducing H-2 dimers into Ga-doped silicon wafers and subsequent annealing. The dissociation of gallium-hydrogen pairs (GaH) under illumination and high temperature conditions is reversible, but a second dissociation phase leads to the irreversible formation of GaH pairs. The dissociation process is likely electron-driven and thermally activated. The activation energy for the dissociation process is estimated to be 0.64-0.71 eV. Lifetime measurements reveal an increase in defect density during the second decrease in pair concentration.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2022)
Article
Energy & Fuels
Jochen Simon, Ronja Fischer-Suesslin, Ruben Zerfass, Leah Kutschera, Paul Dufke, Axel Herguth, Sebastian Roder, Giso Hahn
Summary: Light-and elevated Temperature-induced Degradation (LeTID) remains a challenge for the stability of silicon-based solar cells. This study establishes a correlation between the dominant hydrogen species (H2 and GaH) and the evolving defect concentration in Ga-doped silicon coated with hydrogen-rich amorphous silicon nitride (SiN: H) using sensitive resistivity measurements and photoluminescence/photoconductance decay measurements. The data suggest that the defect concentration is proportional to H2. The investigation also reveals the indiffusion behavior of H from a SiN:H layer during the firing step, showing a strong dependence on peak temperature and a weaker dependence on the cooling rate.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2023)
Article
Materials Science, Multidisciplinary
A. S. Sukhanov, Y. V. Tymoshenko, A. A. Kulbakov, A. S. Cameron, V. Kocsis, H. C. Walker, A. Ivanov, J. T. Park, V. Pomjakushin, S. E. Nikitin, I. V. Morozov, I. O. Chernyavskii, S. Aswartham, A. U. B. Wolter, A. Yaresko, B. Buechner, D. S. Inosov
Summary: FeP is a special material with complex noncollinear spin order. By measuring the spin-excitation spectra, we found that the magnons in FeP have strong anisotropic dispersions. The dominant antiferromagnetic interactions between rigid ferromagnetic spin chains drive the magnetic frustration in FeP.