Article
Physics, Multidisciplinary
Sofia Sanz, Nick Papior, Geza Giedke, Daniel Sanchez-Portal, Mads Brandbyge, Thomas Frederiksen
Summary: This study investigated structures composed of narrow zigzag graphene nanoribbons (GNRs) and found that the beam-splitting effect can survive under Coulomb repulsion and a spin-dependent scattering potential can emerge. The researchers also discovered that this is a general feature with edge-polarized nanoribbons, and near-perfect polarization can be achieved by joining several junctions in series.
PHYSICAL REVIEW LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Junjie Chen, Baofang Liu
Summary: Graphene nanoribbons have the ability to conduct heat, but the precise microscopic mechanisms of heat conduction at room temperature are still not fully understood. Experimental and theoretical research has shown that the transport mechanism in graphene nanoribbons can be ballistic or diffusive, depending on the dimensions. With decreasing dimensions, heat conduction may transition from diffusive to ballistic, leading to a considerable decrease in thermal conductivity.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
Van Minh Nguyen, C. S. Chu
Summary: Studied the suppression of spin relaxation rate caused by magnetic impurities in armchair graphene nanoribbons (AGNR). Found that the spin relaxation rate is significantly suppressed when the Fermi energy approaches a subband band edge. This suppression originates from the quasi-one-dimensional density of states and is manifested through the singular features in the same-site Green's function in AGNR.
Article
Chemistry, Physical
Ziqi Han, Hua Hao, Xiaohong Zheng, Zhi Zeng
Summary: In this study, the spin-dependent transport properties of zigzag graphene nanoribbons (ZGNR) with asymmetric edge hydrogenation and different magnetic configurations were investigated using the non-equilibrium Green's function method combined with density functional calculations. The results showed that changing the magnetic configurations of the electrodes from parallel to antiparallel resulted in substantial changes in the currents in the tunnel junction, leading to a high conductance state and a low conductance state with a tunnel magnetoresistance (TMR) ratio larger than 1 x 10(5)%. Furthermore, an ideal bipolar spin filtering effect was observed in the parallel magnetic configurations, allowing for flexible switching of the spin polarity of current by reversing the bias direction. These findings indicate that asymmetric edge hydrogenation provides an important approach for constructing multi-functional spintronic devices with ZGNRs.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Multidisciplinary Sciences
Song Jiang, Tomas Neuman, Alex Boeglin, Fabrice Scheurer, Guillaume Schull
Summary: In this study, the intrinsic optoelectronic properties of graphene nanoribbons (GNRs) were explored using a scanning tunneling microscope-based method. By transferring the GNRs onto a partially insulating surface, luminescence quenching effects were prevented and localized dark excitons associated with the topological end states of the GNRs were observed.
Article
Multidisciplinary Sciences
Shuo Lou, Bosai Lyu, Jiajun Chen, Lu Qiu, Saiqun Ma, Peiyue Shen, Zhichun Zhang, Yufeng Xie, Qi Liang, Kenji Watanabe, Takashi Taniguchi, Feng Ding, Zhiwen Shi
Summary: Graphene nanoribbons (GNRs) and carbon nanotubes (CNTs) are one-dimensional graphitic materials with promising applications in nanoelectronics. A generic method for the synthesis of both GNRs and CNTs, as well as their heterojunctions, has been developed using catalyzed chemical vapor deposition (CVD) on atomically flat hexagonal boron nitride (h-BN) substrates. The relative ratio of GNRs and CNTs can be controlled by adjusting the growth temperature or feeding gas pressures. Additionally, GNR/CNT intramolecular junctions were achieved by changing the H-2 partial pressure during the growth process.
SCIENTIFIC REPORTS
(2023)
Article
Materials Science, Multidisciplinary
Bonny Dongre, Jesus Carrete, Natalio Mingo, Georg K. H. Madsen
Summary: In this study, we calculate and analyze the lattice thermal conductivity of cubic group-III phosphides. We find that there is a significant disagreement in the literature values for GaP, which can be attributed to the incomplete consideration of long-range interactions and four-phonon scattering. By taking these factors into account, we obtain a calculated thermal conductivity that is in good agreement with the experimental value, highlighting the importance of convergence tests in the calculation process.
Article
Chemistry, Multidisciplinary
Rajeev K. Dubey, Mauro Marongiu, Shuai Fu, Guanzhao Wen, Mischa Bonn, Hai I. Wang, Manuel Melle-Franco, Aurelio Mateo-Alonso
Summary: This study presents an accelerated iterative approach for the synthesis of length-controlled, ultralong, atomically precise graphene nanoribbons (GNRs). The method allows for the exploration of the effects of GNR length on their properties, and enables the purification and characterization of these GNRs.
Article
Chemistry, Physical
Wenhui Niu, Simen Sopp, Alessandro Lodi, Alex Gee, Fanmiao Kong, Tian Pei, Pascal Gehring, Jonathan Naegele, Chit Siong Lau, Ji Ma, Junzhi Liu, Akimitsu Narita, Jan Mol, Marko Burghard, Klaus Muellen, Yiyong Mai, Xinliang Feng, Lapo Bogani
Summary: Only single-electron transistors with a certain level of cleanliness can be used for quantum experiments. The solubility of graphene nanoribbons can be greatly enhanced by edge functionalization, resulting in ultra-clean transport devices with sharp single-electron features. These results demonstrate that molecular graphene can yield exceptionally clean electronic devices directly from solution.
Article
Materials Science, Multidisciplinary
Stevo K. Jacimovski, Jelena S. Lamovec, Jovan P. Setrajcic, Dusan I. Ilic
Summary: This work primarily analyzes the temperature dependence of the relaxation time of elementary excitations quasi-particles (electrons) in graphene. Various relaxation mechanisms are essential in transport processes, and obtaining relaxation times is crucial for understanding the temperature dependence of transport coefficients. The method of Green's functions was used in this work to determine the temperature dependence of the relaxation time of charge carriers in graphene's main scattering processes.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2021)
Article
Chemistry, Physical
Zhen Tong, Alessandro Pecchia, ChiYung Yam, Traian Dumitrica, Thomas Frauenheim
Summary: The presence of nonhexagonal carbon rings in graphene significantly affects its thermal conductivity, but there are still some dense and ordered arrangements of carbon rings in 2D carbon allotropes that allow thermal energy transfer. The phonon thermal conductivity is lowered while the electron thermal conductivity is enhanced due to the nonhexagonal rings.
ADVANCED ENERGY MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Ethan Chi Ho Wen, Peter H. Jacobse, Jingwei Jiang, Ziyi Wang, Ryan D. McCurdy, Steven G. Louie, Michael F. Crommie, Felix R. Fischer
Summary: The research demonstrates the assembly and spectroscopic characterization of a one-dimensional Kondo spin chain formed by a chevron-type GNR physisorbed on Au(111). By introducing nitrogen core doping, magnetic moments within the core of the GNR are generated when it is placed on Au.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Multidisciplinary Sciences
I Taktak, M. Kapfer, J. Nath, P. Roulleau, M. Acciai, J. Splettstoesser, I Farrer, D. A. Ritchie, D. C. Glattli
Summary: In this study, a novel interferometric approach was used to demonstrate that anyons maintain quantum coherence while propagating. The results have positive implications for achieving controlled quantum coherent braiding of anyons.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Ryan D. McCurdy, Aidan Delgado, Jingwei Jiang, Junmian Zhu, Ethan Chi Ho Wen, Raymond E. Blackwell, Gregory C. Veber, Shenkai Wang, Steven G. Louie, Felix R. Fischer
Summary: Metallic graphenenanoribbons (GNRs) are essential for low-dimensional functional materials technology as 1D interconnects for electronic and quantum information transport. However, the design and assembly of metallic GNRs have been hindered by the structural constraints in on-surface bottom-up synthesis and limited control over the orientation and sequence of asymmetric monomer building blocks during polymerization. In this study, we report the successful synthesis of GNRs with robust metallic states by embedding a symmetric zero-mode superlattice along the backbone.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Review
Chemistry, Multidisciplinary
Wenhui Niu, Ji Ma, Xinliang Feng
Summary: This article presents the current research status of graphene nanoribbons (GNRs), with a focus on the bottom-up synthesis, characterization, and optoelectronic properties of cove or fjord-edged cGNRs. It also discusses the challenges and prospects in the design and synthesis of cGNRs, aiming to stimulate further development through interdisciplinary collaborations.
ACCOUNTS OF CHEMICAL RESEARCH
(2022)
Article
Physics, Condensed Matter
Deepak K. Singh, Arthur Ernst, Vitalii Dugaev, Yiyao Chen, Jagath Gunasekera
Summary: Ruthenates provide a comprehensive research platform to study various novel properties, such as quantum magnetism, superconductivity, and magnetic fluctuation mediated metal-insulator transition (MIT). This overview focuses on the quantum mechanical phenomenology in calcium ruthenium oxide with different compositions.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2022)
Article
Physics, Condensed Matter
S. Kudla, S. Wolski, T. Szczepanski, V. K. Dugaev, E. Ya Sherman
Summary: In this study, we analyze the scattering of electrons by magnetic regions in topological insulators characterized by spin momentum locking. By using perturbation theory and partial wave summation approaches, we investigate the role of system parameters in different scattering regimes. We find that the specific features of spin-momentum locking result in strong differences in the scattering cross-section, compared to conventional spin-independent scattering in semiconductors.
SOLID STATE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
V. A. Stephanovich, E. Kirichenko, V. K. Dugaev, Jackie Harjani Sauco, Belen Lopez Brito
Summary: This article studies the role of disorder in the vibration spectra of molecules and atoms in solids and describes it using a fractional generalization of the quantum-mechanical oscillator problem. The study shows that in the fractional 3D oscillator problem, the orbital momentum degeneracy is lifted and the energy starts to depend on orbital quantum number l. These findings have significant implications for the physical properties of various solids, including multiferroics and oxide heterostructures.
SCIENTIFIC REPORTS
(2022)
Article
Physics, Multidisciplinary
X. -g. Wang, Guang-hua Guo, A. Dyrdal, J. Barnas, V. K. Dugaev, S. S. P. Parkin, A. Ernst, L. Chotorlishvili
Summary: In this study, the helical rotation of skyrmions confined in potentials formed by nanodisks is considered. The skyrmion echo phenomenon is proposed based on numerical and analytical calculations. The physical mechanism behind the formation of skyrmion echo is also discussed.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
V. A. Stephanovich, W. Olchawa, E. Kirichenko, V. K. Dugaev
Summary: In this study, we examine the properties of a soliton solution of the fractional Schrödinger equation with cubic-quintic nonlinearity. We have shown that the substitution of the ordinary Laplacian in the Schrödinger equation by its fractional counterpart can stabilize the soliton texture. By studying the dependence of soliton frequency and norm, we determine the existence and stability regions of the fractional soliton solution. The simple variational approach combined with the VK criterion provides reliable information about soliton structure and stability.
SCIENTIFIC REPORTS
(2022)
Article
Nanoscience & Nanotechnology
D. Maryenko, I. V. Maznichenko, S. Ostanin, M. Kawamura, K. S. Takahashi, M. Nakamura, V. K. Dugaev, E. Ya. Sherman, A. Ernst, M. Kawasaki
Summary: The emergence of an interfacial superconducting state in epitaxial heterostructures of LaTiO3 and KTaO3 has been observed, with the superconductivity transition temperature increasing as the thickness of LaTiO3 decreases. This behavior is observed for both (110) and (111) crystal oriented structures. For thick samples, the finite resistance developing below the superconducting transition temperature increases with increasing LaTiO3 thickness. The (001) oriented heterointerface features a high electron mobility of 250 cm(2) V-1 s(-1) and shows no superconducting transition down to 40 mK, consistent with previous reports. Our results suggest a non-trivial impact of LaTiO3 on the superconducting state and demonstrate the possibility of integrating superconducting KTaO3 interfaces with other oxide materials.
Article
Physics, Multidisciplinary
S. Wolski, V. K. Dugaev, E. Ya. Sherman
Summary: Simultaneous manipulation of charge and spin density distributions is crucial for spintronic applications. This study investigates the formation of coupled spin and charge densities in electron scattering by domains of local magnetization, resulting in position-dependent Zeeman fields due to spin-momentum locking in topological insulators. The scattering pattern depends on electron energy, domain magnetization, and size. By studying scattering by diffraction gratings, it is proposed to design them in topological insulator-based nanostructures to achieve desired distributions of charge and spin densities. These findings are important for engineering magnetic patterns for electron optics and controlling coupled charge and spin evolution.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Xi-guang Wang, Guang-hua Guo, V. K. Dugaev, J. Barnas, J. Berakdar, S. S. P. Parkin, A. Ernst, L. Chotorlishvili
Summary: In this study, we propose and demonstrate a method for controlling the motion of magnetic skyrmions using gigahertz and terahertz electric pulses. By employing polarization-textured pulses, the skyrmion can be manipulated through the interaction with the out-of-plane and in-plane components of the electric field. Micromagnetic calculations and analysis support the experimental feasibility of this control scheme.
Article
Materials Science, Multidisciplinary
V. A. Stephanovich, E. V. Kirichenko, G. Engel, V. K. Dugaev
Summary: We calculate the Ruderman-Kittel-Kasuya-Yosida interaction between impurity spins localized at the surface of an imperfect topological insulator (TI) and show that the warping and tilting of a TI Dirac cone result in a highly anisotropic response to localized spin rotation. The Friedel oscillation strength of the imperfect TI depends on the direction in its plane, which can serve as a fingerprint of the initial Dirac cone distortion. The interplay of spin-orbit interaction, warping and tilting of the initial Dirac cone, and the indirect exchange between localized impurities leads to unusual dynamics.
Article
Materials Science, Multidisciplinary
S. Wolski, M. Inglot, C. Jasiukiewicz, K. A. Kouzakov, T. Maslowski, T. Szczepanski, S. Stagraczynski, R. Stagraczynski, V. K. Dugaev, L. Chotorlishvili
Summary: The spin-dependent scattering process in a system of a topological insulator and a quantum dot is studied, and it is found that an applied external magnetic field leads to the formation of long-range entanglement in the system, which remains robust even in the presence of strong disorder.
Article
Materials Science, Multidisciplinary
X. -g. Wang, L. Chotorlishivil, G. Tatara, A. Dyrdal, Guang-hua Guo, V. K. Dugaev, J. Barnas, S. S. P. Parkin, A. Ernst
Summary: In this study, we comprehensively analyze the phason excitations of a skyrmion lattice in synthetic antiferromagnets using three different methods. We propose an analytical model based on three coupled helices and discover a linear gapless mode in the skyrmion lattice. The results are supported by micromagnetic simulations. We also consider the orbital angular momentum and spin pumping current associated with phason excitations.
Article
Materials Science, Multidisciplinary
L. Chotorlishvili, Xi-guang Wang, A. Dyrdal, Guang-hua Guo, V. K. Dugaev, J. Barnas, J. Berakdar
Summary: In the absence of an external magnetic field and a spin-polarized charge current, an antiferromagnetic system supports two degenerate magnon modes. An applied thermal bias activates the magnetic dynamics, resulting in a magnon flow from the hot to the cold edge. The combination of Dzyaloshinskii-Moriya interaction and external magnetic field substantially enhances the spin current.
Article
Materials Science, Multidisciplinary
V. A. Stephanovich, E. Kirichenko, V. K. Dugaev, J. Barnas
Summary: We theoretically study the dynamic Friedel oscillations of electrons at the surface of a topological insulator (TI) generated by the rotation of a localized impurity spin. Our research shows that the anisotropic response to the localized spin rotation is caused by the spin-orbit interaction in Rashba form. Additionally, the dynamic spin moment emitted by the localized dynamical spin depends on the orientation in the TI plane. This research provides a basis for manipulating spin transport in topological insulators with localized impurity spins.
Article
Materials Science, Multidisciplinary
M. Inglot, V. K. Dugaev, A. Dyrdal, J. Barnas
Summary: Theoretical studies have shown that in graphene with Rashba spin-orbit interaction coupled to a magnetic layer, two one-dimensional edge mode bands propagating along a magnetic domain wall emerge in the energy gap of each Dirac point. These modes associated with different Dirac points are the same, with coefficients containing real and imaginary terms determining the decay of wave functions with distance from the domain wall. Consequently, the system exhibits quantized characteristics such as Chern numbers and chiral modes at the edges, with the number of localized modes at the domain wall determined by the difference in Chern numbers on both sides.
Article
Materials Science, Multidisciplinary
E. K. Petrov, V. N. Men'shov, I. P. Rusinov, M. Hoffmann, A. Ernst, M. M. Otrokov, V. K. Dugaev, T. Menshchikova, E. Chulkov
Summary: This paper suggests a method to realize topologically protected spin-polarized flat bands generated by domain walls in planar magnetic topological insulators, demonstrating their existence near the Fermi level and discussing their potential applications in intrinsic antiferromagnetic topological insulators.
