TY - JOUR AU - Eskandari, Somayeh AU - Koltai, János AU - László, István AU - Kürti, Jenő TI - Molecular Dynamics Study of Nanoribbon Formation by Encapsulating Cyclic Hydrocarbon Molecules inside Single-Walled Carbon Nanotube JF - NANOMATERIALS J2 - NANOMATERIALS-BASEL VL - 14 PY - 2024 IS - 7 PG - 19 SN - 2079-4991 DO - 10.3390/nano14070627 UR - https://m2.mtmt.hu/api/publication/34777533 ID - 34777533 N1 - Department of Biological Physics, Eötvös University, Budapest, 1117, Hungary Department of Theoretical Physics, Budapest University of Technology and Economics, Budapest, 1111, Hungary Export Date: 18 April 2024 Correspondence Address: Kürti, J.; Department of Biological Physics, Hungary; email: jeno.kurti@ttk.elte.hu AB - Carbon nanotubes filled with organic molecules can serve as chemical nanoreactors. Recent experimental results show that, by introducing cyclic hydrocarbon molecules inside carbon nanotubes, they can be transformed into nanoribbons or inner tubes, depending on the experimental conditions. In this paper, we present our results obtained as a continuation of our previous molecular dynamics simulation work. In our previous work, the initial geometry consisted of independent carbon atoms. Now, as an initial condition, we have placed different molecules inside a carbon nanotube (18,0): C5H5 (fragment of ferrocene), C5, C5+H2; C6H6 (benzene), C6, C6+H2; C20H12 (perylene); and C24H12 (coronene). The simulations were performed using the REBO-II potential of the LAMMPS software package, supplemented with a Lennard-Jones potential between the nanotube wall atoms and the inner atoms. The simulation proved difficult due to the slow dynamics of the H abstraction. However, with a slight modification of the parameterization, it was possible to model the formation of carbon nanoribbons inside the carbon nanotube. LA - English DB - MTMT ER - TY - JOUR AU - Al-Assaf, Assem Mustafa Abd-Alrhman AU - Koltai, János AU - Oroszlány, László TI - Surface magnon spectra of nodal loop semimetals JF - PHYSICAL REVIEW B J2 - PHYS REV B VL - 109 PY - 2024 IS - 3 PG - 11 SN - 2469-9950 DO - 10.1103/PhysRevB.109.035161 UR - https://m2.mtmt.hu/api/publication/34715042 ID - 34715042 N1 - Export Date: 2 May 2024 LA - English DB - MTMT ER - TY - GEN AU - Kovács-Krausz, Zoltán AU - Nagy, Dániel AU - Márffy, Albin Máté AU - Karpiak, Bogdan AU - Tajkov, Zoltán AU - Oroszlány, László AU - Koltai, János AU - Nemes Incze, Péter AU - Dash, Saroj P AU - Makk, Péter AU - Csonka, Szabolcs AU - Tóvári, Endre TI - Signature of pressure-induced topological phase transition in ZrTe5 PY - 2023 UR - https://m2.mtmt.hu/api/publication/34719870 ID - 34719870 AB - The layered van der Waals material ZrTe5 is known as a candidate topological insulator (TI), however its topological phase and the relation with other properties such as an apparent Dirac semimetallic state is still a subject of debate. We employ a semiclassical multicarrier transport (MCT) model to analyze the magnetotransport of ZrTe5 nanodevices at hydrostatic pressures up to 2 GPa. The temperature dependence of the MCT results between 10 and 300 K is assessed in the context of thermal activation, and we obtain the positions of conduction and valence band edges in the vicinity of the chemical potential. We find evidence of the closing and subsequent re-opening of the band gap with increasing pressure, which is consistent with a phase transition from weak to strong TI. This matches expectations from ab initio band structure calculations, as well as previous observations that CVT-grown ZrTe5 is in a weak TI phase in ambient conditions. LA - English DB - MTMT ER - TY - JOUR AU - Somayeh, Eskandari AU - Koltai, János AU - László, István AU - Kürti, Jenő TI - Szén nanocsövek belső tere mint kémiai nanoreaktor JF - FIZIKAI SZEMLE J2 - FIZIKAI SZEMLE VL - 73 PY - 2023 IS - 9 SP - 319 EP - 323 PG - 5 SN - 0015-3257 UR - https://m2.mtmt.hu/api/publication/34495390 ID - 34495390 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Eskandari, Somayeh AU - Koltai, János AU - László, István AU - Vaezi, Mehran AU - Kürti, Jenő TI - Formation of nanoribbons by carbon atoms confined in a single-walled carbon nanotube—A molecular dynamics study JF - JOURNAL OF CHEMICAL PHYSICS J2 - J CHEM PHYS VL - 158 PY - 2023 IS - 22 SN - 0021-9606 DO - 10.1063/5.0151276 UR - https://m2.mtmt.hu/api/publication/34014540 ID - 34014540 AB - Carbon nanotubes can serve as one-dimensional nanoreactors for the in-tube synthesis of various nanostructures. Experimental observations have shown that chains, inner tubes, or nanoribbons can grow by the thermal decomposition of organic/organometallic molecules encapsulated in carbon nanotubes. The result of the process depends on the temperature, the diameter of the nanotube, and the type and amount of material introduced inside the tube. Nanoribbons are particularly promising materials for nanoelectronics. Motivated by recent experimental results observing the formation of carbon nanoribbons inside carbon nanotubes, molecular dynamics calculations were performed with the open source LAMMPS code to investigate the reactions between carbon atoms confined within a single-walled carbon nanotube. Our results show that the interatomic potentials behave differently in quasi-one-dimensional simulations of nanotube-confined space than in three-dimensional simulations. In particular, the Tersoff potential performs better than the widely used Reactive Force Field potential in describing the formation of carbon nanoribbons inside nanotubes. We also found a temperature window where the nanoribbons were formed with the fewest defects, i.e., with the largest flatness and the most hexagons, which is in agreement with the experimental temperature range. LA - English DB - MTMT ER - TY - JOUR AU - Kovács-Krausz, Zoltán AU - Tóvári, Endre AU - Nagy, Dániel AU - Márffy, Albin Máté AU - Karpiak, Bogdan AU - Tajkov, Zoltán AU - Oroszlány, László AU - Koltai, János AU - Nemes Incze, Péter AU - Dash, Saroj P. AU - Makk, Péter AU - Csonka, Szabolcs TI - Revealing the band structure of ZrTe5 using multicarrier transport JF - PHYSICAL REVIEW B J2 - PHYS REV B VL - 107 PY - 2023 IS - 7 PG - 10 SN - 2469-9950 DO - 10.1103/PhysRevB.107.075152 UR - https://m2.mtmt.hu/api/publication/33673970 ID - 33673970 LA - English DB - MTMT ER - TY - JOUR AU - Hagymási, Imre AU - Mohd, Isa M.S. AU - Tajkov, Zoltán AU - Márity, K. AU - Oroszlány, László AU - Koltai, János AU - Al-Assaf, Assem Mustafa Abd-Alrhman AU - Kun, Péter AU - Kandrai, Konrád AU - Pálinkás, András AU - Vancsó, Péter AU - Tapasztó, Levente AU - Nemes Incze, Péter TI - Observation of competing, correlated ground states in the flat band of rhombohedral graphite JF - SCIENCE ADVANCES J2 - SCI ADV VL - 8 PY - 2022 IS - 35 PG - 9 SN - 2375-2548 DO - 10.1126/sciadv.abo6879 UR - https://m2.mtmt.hu/api/publication/33090541 ID - 33090541 LA - English DB - MTMT ER - TY - JOUR AU - Tajkov, Zoltán AU - Nagy, Dániel AU - Kandrai, Konrád AU - Koltai, János AU - Oroszlány, László AU - Süle, Péter AU - Horváth, Zsolt Endre AU - Vancsó, Péter AU - Tapasztó, Levente AU - Nemes Incze, Péter TI - Revealing the topological phase diagram of ZrTe5 using the complex strain fields of microbubbles JF - NPJ COMPUTATIONAL MATERIALS J2 - NPJ COMPUT MATER VL - 8 PY - 2022 IS - 1 PG - 7 SN - 2057-3960 DO - 10.1038/s41524-022-00854-z UR - https://m2.mtmt.hu/api/publication/33068873 ID - 33068873 AB - Topological materials host robust properties, unaffected by microscopic perturbations, owing to the global topological properties of the bulk electron system. Materials in which the topological invariant can be changed by easily tuning external parameters are especially sought after. Zirconium pentatelluride (ZrTe5) is one of a few experimentally available materials that reside close to the boundary of a topological phase transition, allowing the switching of its invariant by mechanical strain. Here, we unambiguously identify a topological insulator-metal transition as a function of strain, by a combination of ab initio calculations and direct measurements of the local charge density. Our model quantitatively describes the response to complex strain patterns found in bubbles of few layer ZrTe5 without fitting parameters, reproducing the mechanical deformation-dependent closing of the band gap observed using scanning tunneling microscopy. We calculate the topological phase diagram of ZrTe5 and identify the phase at equilibrium, enabling the design of device architectures, which exploit the topological switching characteristics of the system. LA - English DB - MTMT ER - TY - JOUR AU - Rodriguez, Alvaro AU - Velický, Matej AU - Kalbác, Martin AU - Frank, Otakar AU - Ráhová, Jaroslava AU - Zólyomi, Viktor AU - Koltai, János TI - Activation of Raman modes in monolayer transition metal dichalcogenides through strong interaction with gold JF - PHYSICAL REVIEW B J2 - PHYS REV B VL - 105 PY - 2022 IS - 19 SN - 2469-9950 DO - 10.1103/PhysRevB.105.195413 UR - https://m2.mtmt.hu/api/publication/32854289 ID - 32854289 N1 - J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 2155/3, Prague 8, 182 23, Czech Republic Czech Republic and Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague, Albertov 6, Prague 2, 128 43, Czech Republic Hartree Centre, STFC Daresbury Laboratory, DaresburyWA4 4AD, United Kingdom Department of Biological Physics, Eötvös Loránd University, Pázmány Péter sétány 1/A, Budapest, 1117, Hungary Cited By :2 Export Date: 13 April 2023 AB - Raman spectroscopy has become one of the most utilized methods for the characterization of transition metal dichalcogenides (TMDCs); however, the interpretation of the Raman spectra of TMDC-based heterostructures has been the subject of recent debate. Using a comprehensive combination of micro-Raman and tip-enhanced Raman spectroscopy, accompanied by ab initio simulations of both Raman frequencies and intensities, we show that the activation of the otherwise geometry-forbidden E mode and symmetry-forbidden A1 mode is the fingerprint of the strong interaction between the monolayer MX2 (M is Mo/W, X is S/Se) and the gold substrate, in contrast to the weakly interacting or freestanding MX2. LA - English DB - MTMT ER - TY - GEN AU - Koltai, János AU - B., Fecske AU - E., Kósa AU - Oroszlány, László AU - Tajkov, Zoltán TI - A Bell–CHSH-egyenlőtlenségek tesztelése PY - 2021 PG - 8 UR - https://m2.mtmt.hu/api/publication/32522179 ID - 32522179 LA - Hungarian DB - MTMT ER -