Article
Chemistry, Multidisciplinary
James Lawrence, Alejandro Berdonces-Layunta, Shayan Edalatmanesh, Jesus Castro-Esteban, Tao Wang, Alejandro Jimenez-Martin, Bruno de la Torre, Rodrigo Castrillo-Bodero, Paula Angulo-Portugal, Mohammed S. G. Mohammed, Adam Matej, Manuel Vilas-Varela, Frederik Schiller, Martina Corso, Pavel Jelinek, Diego Pena, Dimas G. de Oteyza
Summary: This study demonstrates two chemical protection/deprotection strategies for chiral graphene nanoribbons, allowing them to survive exposure to air and regain their original electronic properties through hydrogenation and annealing.
Article
Multidisciplinary Sciences
Andoni Ugartemendia, Aran Garcia-Lekue, Elisa Jimenez-Izal
Summary: Recently, silicon atoms have been successfully doped into the edges of single-layer graphene through scanning transmission electron microscopy. In this study, density functional theory is used to model and characterize silicon-doped zigzag-type graphene edges inspired by experiments. The thermodynamic stability is evaluated, and the electronic and magnetic properties of the most relevant edge configurations are revealed. Importantly, it is shown that silicon doping of graphene edges can reverse the spin orientation on adjacent carbon atoms, leading to novel magnetic properties with potential applications in spintronics.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Physical
Lijuan Meng, Jinlian Lu, Yujie Bai, Lili Liu, Jingyi Tang, Xiuyun Zhang
Summary: Understanding the fundamentals of chemical vapor deposition bilayer graphene growth is crucial for its synthesis. Weak interaction between nonepitaxial GTL and Ni(111) substrate favors the nucleation of the adlayer graphene. Employing nonepitaxial GTL makes it easier to heal defects in the adlayer graphene. Results show that high quality adlayer graphene can be grown beneath nonepitaxial GTL on Ni-like substrates.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Jianmei Huang, Qiang Wang, Pengfei Liu, Guang-hui Chen, Yanhui Yang
Summary: The study demonstrated that the interaction strength and interface distance of Gr/h-BN/metal can be tuned by regulating the chemical composition of the surface alloy. The absorption behavior of graphene on h-BN/Cu(111)-Ni and h-BN/Ni(111)-Cu interfaces varied significantly with different Ni/Cu atomic percentages.
Article
Chemistry, Multidisciplinary
Bo Tian, Junzhu Li, Abdus Samad, Udo Schwingenschlogl, Mario Lanza, Xixiang Zhang
Summary: This study demonstrates a method for controlled production of wafer-scale high-quality nucleus-free graphene-mesh metamaterial films and evaluates the carrier mobility of the fabricated films. These findings contribute to the large-scale production of high-quality low-dimensional graphene-mesh metamaterials and provide insights for the application of integrated circuits based on graphene and other 2D metamaterials.
ADVANCED MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Xiaohui Ye, Hao Qiang, Xi Zheng, Ming Qi, Yanwei Yang, Chen Li, Yanling Yang
Summary: A novel approach of laser induced regrowth of graphene was explored to repair the damaged area of graphene film, which showed great potential in metal protection against corrosion, friction, arc-ablating, etc.
MATERIALS CHEMISTRY AND PHYSICS
(2022)
Article
Chemistry, Physical
Da-Jiang Liu, James W. Evans
Summary: Complexation, reconstruction, and sulfide formation processes occur at step edges on the {111} surfaces of coinage metals in the presence of adsorbed S. Molecular Dynamics simulation and machine learning derived potentials are used to study and validate these processes. Key observations include the formation of metal-sulfur complexes, local reconstruction at step edges, and 3D sulfide formation.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Mark J. Haastrup, Mathias H. R. Mammen, Jonathan Rodriguez-Fernandez, Jeppe Lauritsen
Summary: The study investigates the lateral interfaces formed between monolayer MoS2 flakes on Au(111) and two families of armchair graphene nanoribbons (GNRs) created through on-surface assisted Ullmann coupling. The findings show that parallel alignment between GNR armchair edges and MoS2 leads to van der Waals bonded nanoribbons, while a perpendicular orientation results in covalent bonding between a phenyl group of GNR and S on the edge. The presence of MoS2 lowers the temperatures needed for intramolecular dehydrogenation during GNR formation, leading to enhanced hydrogen recombination at the MoS2 edges.
Article
Chemistry, Physical
Fabio Ronci, Stefano Colonna, Roberto Flammini, Maurizio De Crescenzi, Manuela Scarselli, Matteo Salvato, Isabelle Berbezier, Holger Vach, Paola Castrucci
Summary: In this paper, an in-depth study was conducted on the growth of nickel silicides under different conditions. It was found that two different nickel silicides form progressively as the annealing temperature increases. The presence of a graphene layer does not alter the nature of the silicide phases but affects the morphology of the silicide overlayer.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Rocco Davi, Giovanni Carraro, Marija Stojkovska, Marco Smerieri, Letizia Savio, Mikolaj Lewandowski, Jean-Jacques Gallet, Fabrice Bournel, Mario Rocca, Luca Vattuone
Summary: This study investigated the interaction between CO and graphene/Ni(1 1 1) as well as the Boudouard reaction at higher pressure using Near Ambient Pressure X-Ray Photoemission Spectroscopy. The results showed that CO intercalated under the graphene layer, causing partial detachment from the Ni substrate, and the formation of CO2 through the Boudouard reaction was observed. Additionally, CO adsorption was found to occur in strongly interacting areas of the graphene layer.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Guofu Chen, Wenlong Bao, Jiao Chen, Zhaoliang Wang
Summary: This paper studies the thermal rectification phenomenon in graphene supported by a heterogeneous substrate and investigates the influence of heat source temperature and size on the thermal rectification rate. The results show that the heat flux is more easily transferred from the graphene covered on the SiO2 side.
Article
Chemistry, Multidisciplinary
Alessandro Sala, Zhiyu Zou, Virginia Carnevali, Mirco Panighel, Francesca Genuzio, Tevfik O. Mentes, Andrea Locatelli, Cinzia Cepek, Maria Peressi, Giovanni Comelli, Cristina Africh
Summary: The study focuses on lateral quantum confinement to tune the electronic properties of graphene-based nanostructures, with a particular interest in edge topology. It reports the formation of ribbon-like graphene structures with zigzag edges on a Ni(100) substrate, showing 1D electronic states similar to zigzag nanoribbons. Despite being seamlessly incorporated in a matrix of strongly interacting graphene, these structures exhibit electronic properties resembling those of zigzag nanoribbons, as shown through experiments and simulations.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Physical
Yulia G. Polynskaya, Irina Lebedeva, Andrey A. Knizhnik, Andrey M. Popov
Summary: In this study, we investigate the impact of parameters of a model on the accuracy of ab initio calculations of reactions at graphene edges. Specifically, we focus on the reconstruction of zigzag graphene edges and the formation of a pentagon-heptagon pair. Our results show that the nanoribbon should consist of at least 6 zigzag rows and the pair along the nanoribbon axis should be separated by at least 6 hexagons for proper convergence. Furthermore, we find the reaction energy and activation barrier for the formation of an isolated pentagon-heptagon pair. We also observe that these defects only locally reduce the graphene edge magnetization but affect the ordering of spins at opposite nanoribbon edges.
COMPUTATIONAL AND THEORETICAL CHEMISTRY
(2022)
Article
Materials Science, Multidisciplinary
B. P. Reed, M. E. Bathen, J. W. R. Ash, C. J. Meara, A. A. Zakharov, J. P. Goss, J. W. Wells, D. A. Evans, S. P. Cooil
Summary: The research investigates the evolution of the diamond (111) surface as it undergoes reconstruction and subsequent graphene formation using various techniques and analysis. It shows that the C(111)-(2 x 1) reconstructed surface is metallic with intersecting electronic states at the Fermi level, contributing to resolving controversies in the literature. Graphene can be formed at higher temperatures above this reconstructed surface, with little substrate interaction, and the underlying diamond surface can be hydrogen-terminated through plasma processing without removing the graphene layer, forming a graphene-semiconductor interface.
Article
Chemistry, Multidisciplinary
Gabriela Borin Barin, Marco Di Giovannantonio, Thorsten G. Lohr, Shantanu Mishra, Amogh Kinikar, Mickael L. Perrin, Jan Overbeck, Michel Calame, Xinliang Feng, Roman Fasel, Pascal Ruffieux
Summary: The chemical and electronic structure of ultrashort graphene nanoribbons (GNRs) with both armchair and zigzag edges have been studied, along with their chemical reactivity in air.
Article
Chemistry, Multidisciplinary
Xiangzhi Meng, Jenny Moeller, Masoud Mansouri, Daniel Sanchez-Portal, Aran Garcia-Lekue, Alexander Weismann, Chao Li, Rainer Herges, Richard Berndt
Summary: Spin-flip excitations of iron porphyrin molecules on Au(111) were investigated using a low-temperature scanning tunneling microscope. The molecules exhibited two distinct adsorption configurations on the surface, with different magnetic anisotropy energies. Density functional theory calculations showed that the different structures and excitation energies were a result of different occupations of the Fe 3d levels. We demonstrated that the magnetic anisotropy energy could be controlled by changing the adsorption site, orientation, or tip-molecule distance.
Article
Chemistry, Multidisciplinary
W. Dednam, M. A. Garcia-Blazquez, Linda A. Zotti, E. B. Lombardi, C. Sabater, S. Pakdel, J. J. Palacios
Summary: Spin-orbit coupling induces spin charge interconversion phenomena. Chirality-induced spin-selectivity (CISS) is a case of this effect, appearing in various nonmagnetic systems. The origin of CISS in molecular junctions is debated, and our study reveals the role of symmetries in CISS. Metallic nanocontacts can exhibit spin polarization with reduced symmetry, and achiral molecular junctions can also exhibit spin polarization if the entire junction is chiral. Quantum transport calculations support our findings.
Article
Physics, Condensed Matter
Sofia Sanz, Nick Papior, Geza Giedke, Daniel Sanchez-Portal, Mads Brandbyge, Thomas Frederiksen
Summary: We theoretically study electron interference in a Mach-Zehnder-like geometry formed by four parallel pairs of zigzag graphene nanoribbons. By adjusting the interribbon separation, each intersection can function as an electron beam splitter or mirror, allowing for tuneable circuitry with interfering pathways. We evaluate the electron transport properties of these eight-terminal devices and identify pairs of terminals subject to self-interference. The proposed devices have potential applications as magnetic field sensors, detectors of phase shifts induced by local scatterers, and for the study of quantum entanglement.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Chemistry, Multidisciplinary
Cesar Moreno, Xabier Diaz de Cerio, Manuel Vilas-Varela, Maria Tenorio, Ane Sarasola, Mads Brandbyge, Diego Pena, Aran Garcia-Lekue, Aitor Mugarza
Summary: Recent advances in surface-assisted synthesis have demonstrated the ability to create highly anisotropic nanoporous graphene structures by laterally coupling arrays of nanometer wide graphene nanoribbons. In this study, a new nanoporous graphene structure was synthesized in which the interribbon electronic coupling can be controlled by phenylene bridges. The versatility of this structure arises from the multiple configurations of phenylene cross-coupling and the twist angle, which can be altered by interaction with the substrate and other external stimuli.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Beatriz Muniz Cano, Yago Ferreiros, Pierre A. Pantaleon, Ji Dai, Massimo Tallarida, Adriana I. Figueroa, Vera Marinova, Kevin Garcia-Diez, Aitor Mugarza, Sergio O. Valenzuela, Rodolfo Miranda, Julio Camarero, Francisco Guinea, Jose Angel Silva-Guillen, Miguel A. Valbuena
Summary: Magnetic topological insulators with long-range ferromagnetic order and tunable p-type doping of the topological surface states are demonstrated using angle-resolved photoemission spectroscopy on magnetically rare-earth doped topological insulator Bi2Se2Te. The transition from hexagonal to trigonal shape of the TSS and the opening of a bandgap are observed. The experimental results are rationalized by a theoretical model introducing a magnetic Zeeman out-of-plane term in the governing Hamiltonian of the TSS, providing new strategies for controlling magnetic interactions with TSSs and realizing the quantum anomalous Hall effect.
Article
Chemistry, Multidisciplinary
Elena Bartolome, Ludovica Ferrari, Francesco Sedona, Ana Arauzo, Javier Rubin, Javier Luzon, Julia Herrero-Albillos, Mirco Panighel, Aitor Mugarza, Marzio Rancan, Mauro Sambi, Lidia Armelao, Juan Bartolome, Fernando Bartolome
Summary: We investigate the deposition of monolayers and multilayers of {Cr-10} wheels on Au(111) and Cu(111) substrates, and analyze their properties using various spectroscopic techniques. The magnetic behavior of {Cr-10} monolayers on Ag(111) and Cu(111) exhibits slight differences compared to the bulk, which can be rationalized by considering the impact of surface deposition on intra-wheel coupling interactions. The sensitivity of {Cr-10} to molecular distortions suggests potential applications for controlling magnetism with external stimuli.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Yolanda Manzanares-Negro, Jiamin Quan, Maedeh Rassekh, Mohammed Moaied, Xiaoqin Li, Pablo Ares, Juan Jose Palacios, Julio Gomez-Herrero, Cristina Gomez-Navarro
Summary: The performance of electronic and optoelectronic devices is strongly influenced by charge carrier injection through metal-semiconductor contacts. A new strategy to reduce the contact resistance of MoS2 through local pressurization is reported. Theoretical simulations and experimental results show significant improvements in contact resistance and field-effect mobility of MoS2 devices under high pressure conditions. This research suggests a novel approach for improving the performance of MoS2 devices and exploring emergent phenomena through mechano-electric modulation.
Article
Chemistry, Multidisciplinary
Federico Binda, Stefano Fedel, Santos Francisco Alvarado, Paul Noel, Pietro Gambardella
Summary: The study investigates the spin-orbit torques (SOTs) and spin Hall magnetoresistance generated by Bi0.9Sb0.1(0001) when coupled with FeCo, confirming its effectiveness as a spin-injector material. The research finds that charge-to-spin conversion in single-crystal Bi0.9Sb0.1(0001) is isotropic despite the strong anisotropy of the topological surface states. Additionally, the damping-like SOT displays non-monotonic temperature dependence, with a minimum occurring at 20 K.
ADVANCED MATERIALS
(2023)
Article
Physics, Multidisciplinary
Giacomo Sala, Hanchen Wang, William Legrand, Pietro Gambardella
Summary: The study reported the existence of a large Hanle magnetoresistance in single layers of Mn with weak spin-orbit coupling, attributed to the orbital Hall effect. Simultaneous observation of a sizable Hanle magnetoresistance and vanishing small spin Hall magnetoresistance in BiYIG/Mn bilayers confirmed the orbital origin of both effects. Estimates revealed the presence of an orbital Hall angle, an orbital relaxation time, and a diffusion length in disordered Mn.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
Chao Yun, Zhongyu Liang, Ales Hrabec, Zhentao Liu, Mantao Huang, Leran Wang, Yifei Xiao, Yikun Fang, Wei Li, Wenyun Yang, Yanglong Hou, Jinbo Yang, Laura J. Heyderman, Pietro Gambardella, Zhaochu Luo
Summary: By reversibly converting the magnetic coupling between nanomagnets through solid-state ionic gating, we have achieved a voltage-controlled phase transition in artificial spin ices and demonstrated an electrically programmable Ising network. This provides new avenues for exploring collective phenomena, designing nanomagnet-based devices, and neuromorphic computers.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Cesar Moreno, Xabier Diaz de Cerio, Manuel Vilas-Varela, Maria Tenorio, Ane Sarasola, Mads Brandbyge, Diego Pena, Aran Garcia-Lekue, Aitor Mugarza
Summary: Recent advances in surface-assisted synthesis have shown that graphene nanoribbons can be coupled laterally to form nanoporous graphene structures. This graphene nanoarchitecture consists of weakly coupled semiconducting nanochannels with electron propagation characterized by interchannel quantum interferences. By utilizing phenylene bridges, the electronic coupling between the nanoribbons in the nanoporous graphene structure can be controlled, providing versatility through different phenylene cross-coupling configurations and twist angles. Simulation results demonstrate the ability to switch on/off or modulate the interribbon coupling using the chemical or conformational knob. Molecular bridges offer efficient tools for engineering quantum transport and anisotropy in carbon-based 2D nanoarchitectures.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Zhentao Liu, Zhaochu Luo, Ivan Shorubalko, Christof Vockenhuber, Laura J. Heyderman, Pietro Gambardella, Ales Hrabec
Summary: Strong, adjustable magnetic couplings are important for devices based on magnetic materials. This study demonstrates strong exchange-based coupling between arbitrarily shaped regions of a single ferrimagnetic layer by spatially patterning the compensation temperature. The coupling generates large lateral exchange coupling fields and can be used to control the switching of magnetically compensated dots with an electric current.
Article
Physics, Multidisciplinary
Juan Jose Esteve-Paredes, Juan Jose Palacios
Summary: We present a comprehensive study of the velocity operator, v = hh [ H, r ] , when used in i crystalline solids calculations. Our work summarizes the different approaches found in the literature, but never connected before in a comprehensive manner. We show how one can compute the velocity matrix elements following two different routes, either by explicitly using the commutator or by relying on the Berry connection. We also compare with its real-space evaluation through the identification with the canonical momentum operator when possible.
SCIPOST PHYSICS CORE
(2023)
Article
Chemistry, Multidisciplinary
W. Dednam, M. A. Garcia-Blazquez, Linda A. Zotti, E. B. Lombardi, C. Sabater, S. Pakdel, J. J. Palacios
Summary: Spin-orbit coupling leads to various spin-charge interconversion phenomena, one of which is chirality-induced spin-selectivity (CISS). CISS appears in different situations ranging from inorganic materials to molecular devices, and the origin of CISS in molecular junctions is currently debated. This study reveals that both electrode symmetries and molecular symmetries play important roles in the emergence of spin-polarization and CISS. The findings also show that standalone metallic nanocontacts can exhibit spin-polarization when introducing relative rotations that reduce symmetry. Moreover, molecular junctions with achiral molecules can exhibit spin-polarization if the entire junction is chiral in a specific way. The predictions of this study have been confirmed by quantum transport calculations based on density functional theory.
Article
Nanoscience & Nanotechnology
Vinicius G. Garcia, Nathanael N. Batista, Diego A. Aldave, Rodrigo B. Capaz, Juan Jose Palacios, Marcos G. Menezes, Wendel S. Paz
Summary: In this study, a van der Waals heterostructure consisting of isostructural nanoribbons of Sb2S3 and Sb2Se3 is demonstrated to have a direct band gap and a typical type-II band alignment, making it suitable for optoelectronics and solar energy conversion. Optical absorption spectra show broad profiles in the visible and UV ranges for all configurations, indicating their potential for photodevices.
ACS APPLIED MATERIALS & INTERFACES
(2023)
