Article
Chemistry, Multidisciplinary
Niklas Friedrich, Rodrigo E. Menchon, Iago Pozo, Jeremy Hieulle, Alessio Vegliante, Jingcheng Li, Daniel Sanchez-Portal, Diego Pena, Aran Garcia-Lekue, Jose Ignacio Pascual
Summary: Spin-hosting graphene nanostructures offer potential for metal-free elementary quantum spintronic devices. In this study, a narrow graphene nanoribbon doped with boron heteroatoms was fabricated and exhibited metallic behavior with localized spin 1/2 states. The transport measurements and conductance spectra confirmed the presence of localized spin states in the nanoribbon. Density functional theory analysis explained the metallic character and spin localization due to the boron atoms. This research opens up possibilities for electronic addressing and controlling carbon spins in real device architectures.
Article
Chemistry, Multidisciplinary
Tao Wang, Sofia Sanz, Jesus Castro-Esteban, James Lawrence, Alejandro Berdonces-Layunta, Mohammed S. G. Mohammed, Manuel Vilas-Varela, Martina Corso, Diego Pena, Thomas Frederiksen, Dimas G. de Oteyza
Summary: This study characterized the magnetic states of chiral graphene nanoribbons by substitution of hydrogen atoms with ketones, leading to the generation of unpaired pi radicals that can interact via exchange coupling. The interactions between these radical states were found to depend significantly on factors such as chirality and the presence of ketone functionalization, and the parameters for accurately describing these systems within the mean-field Hubbard model were determined. Overall, this research provides insights for theoretically modeling and designing GNR-based nanostructures with tunable magnetic properties.
Article
Chemistry, Multidisciplinary
Daniel J. Rizzo, Jingwei Jiang, Dharati Joshi, Gregory Veber, Christopher Bronner, Rebecca A. Durr, Peter H. Jacobse, Ting Cao, Alin Kalayjian, Henry Rodriguez, Paul Butler, Ting Chen, Steven G. Louie, Felix R. Fischer, Michael F. Crommie
Summary: The paper discusses the fabrication and characterization of deterministic GNR quantum dots with orbital character defined by zero-mode states from nontrivial topological interfaces. The results are supported by density-functional theory and tight-binding calculations, showing that the orbital hopping between topological zero-mode states can be tuned based on the bonding geometry of the interconnecting region. This study demonstrates the potential of topological zero modes in designer quantum dots and advanced electronic devices.
Article
Chemistry, Physical
Prashant P. Shinde, Jia Liu, Thomas Dienel, Oliver Groening, Tim Dumslaff, Markus Muhlinghaus, Akimitsu Narita, Klaus Muellen, Carlo A. Pignedoli, Roman Fasel, Pascal Ruffieux, Daniele Passerone
Summary: A new bottom-up synthesis strategy enables the fabrication of graphene nanoribbons with well-defined width and non-trivial edge structures from specific molecular precursors. The modified nanoribbons exhibit unique electronic properties compared to pristine ones, with a finite band gap and absence of localized edge states. Experimental and theoretical investigations show noticeable localization of electronic states at the modified edges, providing insight into enhancing features for potential applications in nanoelectronics and spintronics.
Article
Chemistry, Multidisciplinary
Raj Kumar Paudel, Chung-Yuan Ren, Yia-Chung Chang
Summary: We implemented a semi-empirical pseudopotential (SEP) method to calculate the band structures of graphene and graphene nanoribbons. The SEP includes both local and non-local terms, fitted to first-principles calculations based on DFT. With only a handful of parameters, our method accurately reproduces the band structures obtained by DFT for graphene. We also applied the SEP method to calculate the band structures of graphene nanoribbons, obtaining results close to DFT by adding a correction term to the local pseudopotentials on the nanoribbon edges.
Article
Materials Science, Multidisciplinary
Lingling Song, Yan Zhang, Runlong Ye, Lu Liu, Canglong Wei, Han Zhao, Xiaohong Zheng
Summary: In this paper, a new spin control method called spin splitter is proposed. By embedding h-BN nanoribbon in ferromagnetic ZGNRs, the two spin channels are separated into two isolated branches. Based on density functional theory, it is found that h-BN nanoribbon acts as a perfect spin splitter. This finding is of great significance in spintronics.
Article
Chemistry, Physical
Mengmeng He, Xiao-Qiang Liu, Meijun Li, Yi Yang, Zeqin Chen, Weidong Jiang, Haiming Tang, Onyekachi Raymond
Summary: In this study, density functional theory was used to modify armchair-edged graphene nanoribbons and zigzag-edged graphene nanoribbons through functionalization, creating a candidate for designing formaldehyde sensors. Simulation results showed that the interactions between the functionalized nanoribbons and formaldehyde were mainly determined by multiple hydrogen bonds. Specifically designed functionalized nanoribbons could act as a physical sensor for detecting formaldehyde molecules.
APPLIED SURFACE SCIENCE
(2022)
Article
Physics, Multidisciplinary
Dominik Szczesniak, Ewa A. Drzazga-Szczesniak
Summary: This study investigates the impact of non-adiabatic effects on the superconducting state in electron-doped graphene, revealing a significant reduction in key thermodynamic properties such as critical temperature and superconducting gap. Furthermore, it is found that the influence of non-adiabatic effects increases with the rise in depairing Coulomb interaction.
Article
Physics, Condensed Matter
Sharieh Jamalzadeh Kheirabadi, Rahim Ghayour, Maryam Sanaee
Summary: In this research, a new gas sensor structure called Attached FAGNR tube (AFAGNT) was designed using carbon nanotube material. The AFAGNT showed significant sensitivity to CO gas while being insensitive to CO2 gas.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Materials Science, Multidisciplinary
Mason Protter, Rufus Boyack, Frank Marsiglio
Summary: This paper provides a derivation of the Eliashberg theory based on a functional-integral approach and considers its Gaussian-fluctuation extension. The functional method allows for a systematic derivation of the Cooper and density-channel interactions in the Gaussian-fluctuation response.
Article
Physics, Applied
Junwei Yang, Hua Zhao, Lei Ke, Xing Liu, Shengbin Cao
Summary: This study investigates the effects of different edge morphologies of graphene on potassium atom adsorption and diffusion through density functional theory calculations. The results show that ZGNRs terminating with -H promote potassium atom adsorption and have minimal impact on the diffusion barrier in the edge region.
INTERNATIONAL JOURNAL OF MODERN PHYSICS B
(2021)
Article
Optics
Zhen-Yang Hu, Cai-Juan Xia, Xiao-Jie Tang, Ting-Ting Zhang, Jiao Yu, Yang Liu
Summary: This paper investigates the electronic transport properties of tailored triangular zigzag graphene nanoribbons with different orientations using density functional theory (DFT). The results show that the orientation of the triangular structure significantly affects the electron transport capacity of the molecular device, with the upward triangular graphene exhibiting potential for future molecular device designs due to its remarkable negative differential resistance behaviors.
Article
Multidisciplinary Sciences
Austin J. Way, Robert M. Jacobberger, Nathan P. Guisinger, Vivek Saraswat, Xiaoqi Zheng, Anjali Suresh, Jonathan H. Dwyer, Padma Gopalan, Michael S. Arnold
Summary: This study demonstrates a method to synthesize one-dimensional graphene nanoribbons narrower than 5 nm using molecular-scale carbon seeds and chemical vapor deposition (CVD). The nanoribbons are grown by selectively extending the seeds along a single direction. The synthesized nanoribbons have small standard deviation, large aspect ratio, and tunable width. Field-effect transistors based on the nanoribbons show a significant difference in off-current due to the variation in nanoribbon widths.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Na Cheng, Feng Chen, Nan Wang, Zhuocong Xiao, Colm Durkan, Liuyue Zhang, Jianwei Zhao
Summary: The study focuses on the potential applications of tailored graphene nanoribbons (t-GNRs), and systematically investigates the size effects on electronic transport in t-GNR-based molecular junctions. Manufacturing errors during processing or synthesis of t-GNRs can lead to deviations from design values, affecting device performance significantly. Width of the junction is found to have a significant impact on conductivity, while chain length has little influence on electronic transport. Additionally, increasing the width of the junction shows a clear odd-even variation in transport behavior.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Physics, Condensed Matter
Roya Majidi
Summary: The study examined the structural and electronic properties of edge functionalized S-graphene nanoribbons, revealing that their electronic properties are highly influenced by ribbon width and edge functionalization. The metallic properties of S-graphene nanoribbons depend on the type of functionalization groups, with sulfur and chlorine edge-functionalized ribbons displaying metallic properties while hydrogen, fluorine, and hydroxyl functionalized ribbons are semiconductors. Functionalization was determined to be an effective method for tuning the electronic properties of S-graphene nanoribbons for various devices and sensing applications.
SOLID STATE COMMUNICATIONS
(2021)
Article
Chemistry, Multidisciplinary
Xin Chen, Cian Bartlam, Vicent Lloret, Narine Moses Badlyan, Stefan Wolff, Roland Gillen, Tanja Stimpel-Lindner, Janina Maultzsch, Georg S. Duesberg, Kathrin C. Knirsch, Andreas Hirsch
Summary: This study demonstrates a novel approach to constructing bisfunctionalized MoS2 hybrid structures by successively reacting activated MoS2 with alkyl iodide and aryl diazonium salts, showing higher reactivity compared to adducts formed through reactions with diazonium salts. The systematic study on formation and reactivity of covalently functionalized MoS2 hybrids provides practical guidance for tailoring the properties of 2D MoS2 for various potential applications.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Felix Kampmann, Leela S. Panchakarla, Roland Gillen, Reshef Tenne, Janina Maultzsch
Summary: Using density functional theory calculations, we identified the vibrational modes of the misfit-layer compound LaS-CrS2, and observed the influence of charge transfer and structural changes on the vibrational properties. Through comparison of different model systems, we assigned specific vibrational frequencies to phonon branches of the sublayers in the supercell structure.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Xin Chen, Malte Kohring, M'hamed Assebban, Bartlomiej Tywoniuk, Cian Bartlam, Narine Moses Badlyan, Janina Maultzsch, Georg S. Duesberg, Heiko B. Weber, Kathrin C. Knirsch, Andreas Hirsch
Summary: The study presents an efficient method to pattern 2D MoS2 into delicate ribbon patterns with a minimum feature size of 2 micrometers, combining electron beam lithography with surface covalent functionalization. The patterned monolayer MoS2 domain consists of a well-defined heterophase homojunction and alternately distributed surface characteristics, showing great potential for further exploration in MoS2 based devices.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Materials Science, Multidisciplinary
Matthias A. Popp, Malte Kohring, Alexander D. Fuchs, Sascha Korn, Narine Moses Badlyan, Janina Maultzsch, Heiko B. Weber
Summary: The study investigates the photoluminescence of MoS2 monolayers in optical cavities with the use of a squeezable nanojunction (SNJ) that can be tuned in operando. The results show strong distortions of PL spectra due to the tunable cavity and emphasize the significant influence of the local electromagnetic mode budget on spectral properties. The experiment highlights the versatile application range of the SNJ technique for combining electronic functionality with optical access and a tunable light-matter interface.
Article
Materials Science, Multidisciplinary
Benjamin M. Janzen, Roland Gillen, Zbigniew Galazka, Janina Maultzsch, Markus R. Wagner
Summary: This study investigates the first- and second-order Raman modes of monoclinic beta-Ga2O3 through a combined experimental-theoretical approach. The phonon frequencies of beta-Ga2O3 are determined through polarized micro-Raman spectroscopy measurements on single crystals. By utilizing density functional perturbation theory and group-theoretical analysis, the mode frequencies, phonon dispersion relation, and phonon density of states are calculated and correlated with experimental results. This study also demonstrates the simultaneous determination of Raman, IR, and acoustic phonons in beta-Ga2O3 using second-order Raman spectroscopy.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Tobias Dierke, Daniela Dasler, Tamara Nagel, Frank Hauke, Andreas Hirsch, Janina Maultzsch
Summary: In this study, we investigate the degree of covalent functionalization of graphene on different two-dimensional (2D) materials. The underlying substrate has a strong influence on the functionalization of graphene. Patterning the underlying material is a versatile method that preserves the high-quality properties of graphene, allowing for spatially defined functionalization.
ACS APPLIED NANO MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Hannes Van Avermaet, Pieter Schiettecatte, Sandra Hinz, Luca Giordano, Fabio Ferrari, Celine Nayral, Fabien Delpech, Janina Maultzsch, Holger Lange, Zeger Hens
Summary: This study presents a synthesis protocol for forming InP-based quantum dots with high quantum efficiency across the full visible spectrum. By introducing specific interfacial treatments and a core/shell/shell structure, the researchers achieved the intended emission color while minimizing line broadening caused by lattice mismatch. The realization of this high quantum efficiency in full-spectrum color conversion will greatly facilitate research into light-matter interaction.
Article
Nanoscience & Nanotechnology
Moritz Quincke, Tibor Lehnert, Itai Keren, Narine Moses Badlyan, Fabian Port, Manuel Goncalves, Michael J. Mohn, Janina Maultzsch, Hadar Steinberg, Ute Kaiser
Summary: Understanding the positions, densities, and atomic structures of crystallographic defects is crucial for the electronic and optical applications of two-dimensional materials and their vertical heterostructures. By combining device measurements with atomically resolved transmission electron microscopy (TEM) experiments, researchers have developed a generic sample platform that allows imaging of freestanding 2D materials in TEM, followed by experiments on the same sample area placed on an arbitrary substrate or embedded into a heterostructure device. The platform enables the creation and manipulation of atomic defects using the electron beam.
ACS APPLIED NANO MATERIALS
(2022)
Article
Chemistry, Inorganic & Nuclear
Franz Kamutzki, Maged F. Bekheet, Soren Selve, Felix Kampmann, Konrad Siemensmeyer, Delf Kober, Roland Gillen, Markus Wagner, Janina Maultzsch, Aleksander Gurlo, Dorian A. H. Hanaor
Summary: A novel sodium gadolinium pyroxene (NaGdSi2O6) was successfully synthesized and its crystal structure was determined. The sodium gadolinium pyroxene showed weak antiferromagnetic coupling, but no long-range magnetic order was observed above 2 K.
JOURNAL OF SOLID STATE CHEMISTRY
(2023)
Article
Chemistry, Physical
Pascal Buettner, Florian Scheler, Dirk Doehler, Maissa K. S. Barr, Michael Bosch, Marcel Rey, Tadahiro Yokosawa, Sandra Hinz, Janina Maultzsch, Erdmann Spiecker, Nicolas Vogel, Ignacio Minguez-Bacho, Julien Bachmann
Summary: This study addresses the issue of morphological rearrangement of Sb2S3 during thermal crystallization by introducing a sacrificial capping layer of ZnO and oxidative treatment of the Sb2S3 surface. The concentric p-i-n heterojunction solar cells fabricated using this approach show a high refractive index contrast and achieve >5% overall solar energy conversion efficiency with a simple light absorber phase of only 35 nm thickness.
Article
Materials Science, Multidisciplinary
Narine Moses Badlyan, Nina Pettinger, Niklas Enderlein, Roland Gillen, Xin Chen, Wanzheng Zhang, Kathrin C. Knirsch, Andreas Hirsch, Janina Maultzsch
Summary: This study presents a Raman investigation of MoS2 powders and MoS2 individual layers functionalized with organic molecules. It is found that the functionalized MoS2 powders are oxidized into MoO3 upon increasing temperature, while the mechanically exfoliated individual MoS2 layers do not undergo the same transformation. During the covalent functionalization, few-layer MoS2 undergoes a partial transition from the 2H to the 1T' crystallographic phase.
Proceedings Paper
Engineering, Electrical & Electronic
Fabian Mooshammer, Philipp Merkl, Simon Ovesen, Samuel Brem, Anna Girnghuber, Kai-Qiang Lin, Marlene Liebich, Chaw-Keong Yong, Rolang Gillen, Janina Maultzsch, John M. Lupton, Ermin Malic, Rupert Huber
2021 CONFERENCE ON LASERS AND ELECTRO-OPTICS EUROPE & EUROPEAN QUANTUM ELECTRONICS CONFERENCE (CLEO/EUROPE-EQEC)
(2021)
Article
Materials Science, Multidisciplinary
Daniel Erkensten, Samuel Brem, Koloman Wagner, Roland Gillen, Rauel Perea-Causin, Jonas D. Ziegler, Takashi Taniguchi, Kenji Watanabe, Janina Maultzsch, Alexey Chernikov, Ermin Malic
Summary: This study demonstrates the key role of dark intervalley states in monolayer WSe2 in governing the exciton-exciton annihilation process, and reveals a characteristic temperature dependency of Auger scattering in this class of materials with excellent agreement between theory and experiment. The research provides microscopic insights into the efficiency of technologically relevant Auger scattering channels within atomically thin semiconductors' remarkable exciton landscape.
Article
Materials Science, Multidisciplinary
Benjamin M. Janzen, Piero Mazzolini, Roland Gillen, Vivien F. S. Peltason, Linus P. Grote, Janina Maultzsch, Roberto Fornari, Oliver Bierwagen, Markus R. Wagner
Summary: Gallium oxide (Ga2O3) is a wide bandgap material with potential applications in power electronics and photodetectors. The orthorhombic kappa phase is of particular interest for its ferroelectric behavior and potential for high-quality electron gases. Investigation into the phonon modes of the material provides insights into its crystal structure and vibrational properties.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Materials Science, Multidisciplinary
Benjamin M. Janzen, Piero Mazzolini, Roland Gillen, Andreas Falkenstein, Manfred Martin, Hans Tornatzky, Janina Maultzsch, Oliver Bierwagen, Markus R. Wagner
Summary: The study investigates the phonon modes of beta-Ga2O3 in different oxygen isotope compositions and reveals that the substitution of oxygen isotopes affects the Raman frequencies. By conducting experiments and theoretical calculations, the study identifies the atomistic origin of Raman modes and presents a blueprint for future identification of different point defects in Ga2O3 using Raman spectroscopy.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
