Article
Physics, Multidisciplinary
C. L. Tschirhart, Evgeny Redekop, Lizhong Li, Tingxin Li, Shengwei Jiang, T. Arp, O. Sheekey, Takashi Taniguchi, Kenji Watanabe, M. E. Huber, Kin Fai Mak, Jie Shan, A. F. Young
Summary: Magnetic switching via spin-orbit torque is demonstrated in a moire bilayer, providing a platform for spintronic applications.
Article
Multidisciplinary Sciences
Yihang Zeng, Zhengchao Xia, Kaifei Kang, Jiacheng Zhu, Patrick Knueppel, Chirag Vaswani, Kenji Watanabe, Takashi Taniguchi, Kin Fai Mak, Jie Shan
Summary: This paper reports the discovery of integer and fractional Chern insulators in small-angle twisted bilayer MoTe2 at zero magnetic field, and provides experimental evidence for their topological properties. The research findings pave the way for the realization of quantized fractional Hall conductance and anyonic excitation and braiding in semiconductor moire materials.
Article
Multidisciplinary Sciences
Zengming Meng, Liangwei Wang, Wei Han, Fangde Liu, Kai Wen, Chao Gao, Pengjun Wang, Cheng Chin, Jing Zhang
Summary: The observation of strong correlations and superconductivity in twisted-bilayer graphene has generated significant interest in fundamental and applied physics. The moire pattern generated by the superposition of two twisted honeycomb lattices is crucial for the emergence of flat electronic bands and other unique properties. In this study, a quantum simulation of the superfluid to Mott insulator transition is demonstrated in twisted-bilayer square lattices using atomic Bose-Einstein condensates.
Article
Materials Science, Multidisciplinary
Saikat Banerjee, Avadh Saxena
Summary: We investigate the topological properties of a stacked multilayer Lieb lattice under intralayer spin-orbit coupling, revealing the emergence of doubly degenerate bands extending over the edge of the Brillouin zone. In the presence of intralayer SOC, these doubly degenerate bands typically form three N-band subspaces.
Article
Optics
Wenchao Yan, Weizhao Cheng, Weijie Liu, Feng Chen
Summary: In recent years, extensive studies have been conducted on topological insulators in one-dimensional periodic systems, particularly Su-Schrieffer-Heeger and trimer lattices. These models support topological edge states protected by lattice symmetry. To further investigate lattice symmetry in one-dimensional topological insulators, a modified version of the conventional trimer lattices called decorated trimer lattices was designed. Experimental demonstrations were conducted using the femtosecond laser writing technique, resulting in the observation of different types of topological edge states. Interestingly, the addition of vertical intracell coupling strength in the model transformed the energy band spectrum and generated unconventional topological edge states with longer localization lengths at a different boundary. This work provides novel insights into one-dimensional topological insulators in photonic lattices.
Article
Chemistry, Multidisciplinary
Felipe Crasto de Lima, Adalberto Fazzio
Summary: Vacancies play a crucial role in the topological transition of transition metal dichalcogenides, inducing a topologically nontrivial phase. Vacancy states in PtSe2 result in a large topological gap within the pristine system gap, allowing the construction of backscattering protected metallic channels embedded in a semiconducting host.
Article
Physics, Multidisciplinary
H. Polshyn, Y. Zhang, M. A. Kumar, T. Soejima, P. Ledwith, K. Watanabe, T. Taniguchi, A. Vishwanath, M. P. Zaletel, A. F. Young
Summary: Strong Coulomb interactions between electrons can lead to the emergence of topological gapped states in partially filled flat bands. Recent observations in twisted monolayer-bilayer graphene have shown insulators with Chern number C=1 at zero-magnetic-field limit, suggesting potential for further exploration of zero-magnetic-field phases with fractional statistics.
Article
Materials Science, Multidisciplinary
R. Pena, V. M. Bastidas, F. Torres, W. J. Munro, G. Romero
Summary: This study investigates the emergence of resonances in periodically driven quantum systems. The authors find that fractional and integer resonances appear when the hopping frequency changes periodically as a fraction or an integer of the on-site interaction. It is shown that there is a fundamental difference between these resonances when the system reaches a Floquet prethermal state, with second-order processes dominating in the case of fractional resonances and first-order processes dominating in the case of integer resonances. The study provides insights into the nonequilibrium quantum many-body system, and highlights the coexistence of Floquet prethermalization and localization, which have potential applications in quantum technologies and quantum information processing.
Article
Physics, Multidisciplinary
Jie Liu, Xiaoyu Mao, Jianxin Zhong, Rudolf A. Romer
Summary: The study investigates the localization properties of generalized two- and three-dimensional Lieb lattices at energies corresponding to flat and dispersive bands using the transfer matrix method (TMM) and finite size scaling (FSS). Results show different scaling properties between flat bands and dispersive bands for all L-d(n), and extended states are observed for disorders W down to W = 0.01t at the flat bands in the three-dimensional case. Additionally, the critical disorder Wc at energy E = 0 decreases as n increases for L-3(n) up to n = 3, indicating a trend in the data.
Article
Physics, Multidisciplinary
Maria Chatzieleftheriou, Alexander Kowalski, Maja Berovic, Adriano Amaricci, Massimo Capone, Lorenzo De Leo, Giorgio Sangiovanni, Luca de Medici
Summary: We demonstrate the existence of a finite-doping quantum critical point (QCP) arising from a first-order Mott transition in the phase diagram of a strongly correlated material. By tuning the chemical potential, we find that the Mott transition evolves into a first-order transition between two metals, leading to a phase separation region ending in the finite-doping QCP. This scenario, demonstrated using a minimal multiorbital Hubbard model, has implications beyond iron-based superconductors and shows a strong analogy with cuprate superconductors.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Yusen Ye, Jimin Qian, Xiao-Wei Zhang, Chong Wang, Di Xiao, Ting Cao
Summary: In this paper, a new moire system is discussed where the emergence of long moire periodicity is due to the presence of two different van der Waals layers with vastly different lattice constants. The first layer is reconstructed using a root 3 by root 3 supercell resembling the Kekule distortion in graphene, leading to nearly commensurate reconstruction with the second layer. This construction allows for coupling between moire bands from remote valleys in momentum space, resulting in valley pseudospin textures that can be controlled by external factors.
Article
Materials Science, Multidisciplinary
Zhenbo Wang, Yu Zhang, Li Wang, Shu Chen
Summary: This study investigates the effect of an additional modulation parameter 8 on the mobility properties of quasiperiodic lattices. Self-duality relation and mobility edge equation are discovered, and the mobility of quasiperiodic systems can be engineered by tuning the parameter 8.
Article
Optics
Yu-Biao Wu, Zhen Zheng, Xiang-Gang Qiu, Lin Zhuang, Guang-Can Guo, Xu-Bo Zou, Wu-Ming Liu
Summary: We propose a valid and feasible scheme for realizing a tunable finite-range interaction for spinless fermions immersed into the bath of bosons. The interaction strength for the fermionic subsystem can be artificially tuned by manipulating bosons, ranging from repulsive to attractive regime. The distance of interaction is locked to the hopping of bosons, making it perfectly clean for the fermionic subsystem.
Article
Optics
Kuldeep Suthar, Pardeep Kaur, Sandeep Gautam, Dilip Angom
Summary: This study investigates the quantum phase transitions of a two-dimensional Bose-Hubbard model with Rashba spin-orbit coupling, showing that different superfluid phases can emerge under different conditions.
Article
Chemistry, Multidisciplinary
Ilya Valmianski, Arantxa Fraile Rodriguez, Javier Rodriguez-Alvarez, Montserrat Garcia del Muro, Christian Wolowiec, Florian Kronast, Juan Gabriel Ramirez, Ivan K. Schuller, Amilcar Labarta, Xavier Batlle
Summary: In this study, local nanoscale changes in the magnetic anisotropy of a Ni film near a V2O3 layer due to an inverse magnetostrictive effect were investigated using temperature-dependent PEEM and XMCD. The reorientation of Ni magnetic domains and increase in coercive field across the SPT of V2O3 were observed, along with a significant change in the magnetic anisotropy of the Ni film. Micromagnetic simulations based on these results were found to be in quantitative agreement with the experimental data. These findings demonstrate the potential of alternative hybrid systems for manipulating magnetic domains at the nanoscale, and for engineering coercive fields in novel data storage architectures.
Article
Materials Science, Multidisciplinary
Nzar Rauf Abdullah, Hunar Omar Rashid, Chi-Shung Tang, Andrei Manolescu, Vidar Gudmundsson
Summary: The study demonstrates the conversion of AA-stacking to AB-stacking in BN-codoped bilayer graphene due to different interlayer interactions between Boron and Nitrogen dopant atoms. The attractive interaction leads to a less stable structure and weaker mechanical properties, while the repulsive interaction results in a more stable structure and improved mechanical performance. Additionally, the attractive interaction induces a small bandgap and deteriorates the thermal and optical properties, whereas the repulsive interaction enhances the bandgap and the overall thermal and optical characteristics of the system.
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2022)
Article
Physics, Condensed Matter
Nzar Rauf Abdullah, Botan Jawdat Abdullah, Hunar Omar Rshid, Chi-Shung Tang, Andrei Manolescu, Vidar Gudmundsson
Summary: In this study, the electronic and optical properties of N or B doped BeO monolayer were investigated using density functional theory. It was found that the band gap of BeO can be tuned and the optical properties can be improved by doping N or B atoms.
SUPERLATTICES AND MICROSTRUCTURES
(2022)
Article
Physics, Condensed Matter
Bashdar Rahman Pirot, Nzar Rauf Abdullah, Andrei Manolescu, Vidar Gudmundsson
Summary: We study thermoelectric transport through a serial double quantum dot coupled to two metallic leads with different thermal energies. Coulomb interactions and coherent effects are found to have significant impacts on the transport properties, leading to extra transport channels and enhanced thermoelectric effects.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Physics, Multidisciplinary
G. A. Nemnes, T. L. Mitran, A. T. Preda, I Ghiu, M. Marciu, A. Manolescu
Summary: This study combines numerical diagonalization with machine learning techniques to predict the eigenvalues and eigenfunctions of many-electron systems, providing an accurate and efficient description of quantum computing architectures in terms of multiple electron states.
Article
Chemistry, Physical
Hadi Rezaie Heris, Movaffaq Kateb, Sigurdur I. Erlingsson, Andrei Manolescu
Summary: In this study, the effects of geometry on the thermal conductivity of silicon and germanium nanowires were investigated using molecular dynamics simulations. The length, diameter, and transverse geometry of the nanowires were considered. Heat transport in tubular nanowires and core/shell structures of Si/Ge and Ge/Si were compared to the heat transport in the separated core and shell components.
SURFACES AND INTERFACES
(2022)
Article
Engineering, Electrical & Electronic
Nzar Rauf Abdullah, Yousif Hussein Azeez, Botan Jawdat Abdullah, Hunar Omar Rashid, Andrei Manolescu, Vidar Gudmundsson
Summary: We report the electronic, thermal, and optical properties of a Germagraphene (GeC) monolayer, considering the effects of buckling. It is found that the band gap of a GeC monolayer can be modified by tuning the planar buckling, leading to significant changes in its thermal and optical properties. Buckled GeC nanosheets exhibit increased optical activities in the visible light region compared to flat GeC, making buckling a promising parameter for improving GeC monolayers for optoelectronic devices.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Chemistry, Physical
N. Filipoiu, Anca G. Mirea, Sarah Derbali, C. -A. Pantis-Simut, D. -V. Anghel, A. Manolescu, Ioana Pintilie, Mihaela Florea, G. A. Nemnes
Summary: The electronic and stability properties of quasi-2D alkylammonium perovskites were studied using density functional theory (DFT) calculations and experimental validations. The effects of halogen ions on band structure, stability, and defect formation energies were analyzed for perovskite structures with different cations and halogens. Experimental validation was performed on pentylammonium-based perovskites, and the results were consistent with the DFT calculations. Thermogravimetric analysis showed enhanced stability of bromide and chloride based compounds, in agreement with theoretical predictions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Nanoscience & Nanotechnology
Hadi Rezaie Heris, K. O. Klausen, Anna Sitek, Sigurdur Erlingsson, Andrei Manolescu
Summary: In this study, we investigate the effects of temperature gradient and chemical potential difference on the charge and heat currents carried by electrons in tubular nanowires with different cross-sectional geometries. We find that the quantum localization of electrons along the edges of the nanowires significantly affects the results. For instance, impurities have a weaker impact on charge and heat transport in triangular shells compared to hexagonal shells, and the thermoelectric current is several times larger in the triangular case for the same temperature gradient as in the hexagonal case.
Article
Nanoscience & Nanotechnology
Kristjan Ottar Klausen, Anna Sitek, Sigurdur I. Erlingsson, Andrei Manolescu
Summary: Flux-periodic oscillations of the superconducting gap in proximitized core-shell nanowires are investigated, comparing the periodicity of oscillations in the energy spectrum between cylindrical nanowires and nanowires with hexagonal and square cross-section geometries, while also considering the effects of Zeeman and Rashba spin-orbit interaction. A transition from h/e to h/2e periodicity is observed, depending on the chemical potential and corresponding to degeneracy points of the angular momentum quantum number. In the case of a thin shell of a square nanowire, solely h/e periodicity is found in the infinite wire spectrum, resulting from energy separation between the lowest groups of excited states.
Article
Computer Science, Artificial Intelligence
Calin-Andrei Pantis-Simut, Amanda Teodora Preda, Lucian Ion, Andrei Manolescu, George Alexandru Nemnes
Summary: Accurate and efficient calculation of ground state properties in interacting quantum systems is crucial for the design of nanoelectronic devices. The exact diagonalization method, although considered the gold-standard, becomes computationally prohibitive for larger instances, thus machine learning techniques such as cGAN-based pix2pix can provide a significant reduction in computational time while maintaining reasonable accuracy. In this study, we use pix2pix to predict ground state densities using randomly generated confinement potentials and also investigate other mappings related to interacting and non-interacting densities.
MACHINE LEARNING-SCIENCE AND TECHNOLOGY
(2023)
Article
Optics
Blazej Jaworowski, Michael Iversen, Anne E. B. Nielsen
Summary: It has been recently shown that fractional quantum Hall states can be defined on fractal lattices. In this study, approximate parent Hamiltonians for bosonic Laughlin states at half filling were sought, which contained only onsite potentials and two-site hopping with interaction generated implicitly by hardcore constraints. The ground states of some models exhibited high overlap with the model states when third-neighbor hopping terms were considered, and increasing the maximum hopping distance improved the overlap. The braiding properties of model quasihole wave functions and Hamiltonian models were also analyzed for small system sizes.
Article
Materials Science, Multidisciplinary
Kristjan Ottar Klausen, Anna Sitek, Sigurdur I. Erlingsson, Andrei Manolescu
Summary: By solving the Bogoliubov-de Gennes Hamiltonian, the electron-hole coherence within a partially proximitized n-doped semiconductor shell of a core-shell nanowire heterostructure is investigated numerically and compared with the Andreev reflection interpretation of proximity induced superconductivity. The effect of partial proximitization on the localization probability and superconductivity gap is explored for radial, angular, and longitudinal cases. It is found that the boundary conditions impose localization probability maxima in the center of the shell for the radial case, while the essence of Andreev reflection is observed in the angular and longitudinal cases.
Article
Materials Science, Multidisciplinary
Vidar Gudmundsson, Vram Mughnetsyan, Nzar Rauf Abdullah, Chi-Shung Tang, Valeriu Moldoveanu, Andrei Manolescu
Summary: The orbital and spin magnetization of a cavity-embedded quantum dot array in a GaAs heterostructure is calculated using quantum-electrodynamical density-functional theory. The numerical results show the polarizing effects of the cavity photon field and nontrivial changes in the orbital magnetization. The study discusses the dependence of the magnetization on the electron number in each dot and the electron-photon coupling strength, and identifies the formation of magnetoplasmon-polaritons in the dots.
Article
Materials Science, Multidisciplinary
Blazej Jaworowski, Anne E. B. Nielsen
Summary: In this study, we search for short-range Hamiltonians that maximize the overlaps with lattice Moore-Read states in finite spin-1 kagome systems. We start with an exact long-range parent Hamiltonian obtained from conformal field theory, and apply a truncation procedure to retain only short-range terms and define the Hamiltonian on a torus. Finally, we optimize the remaining coefficients to obtain maximized overlaps between the exact diagonalization results and the model ground states.
Article
Materials Science, Multidisciplinary
Vidar Gudmundsson, Vram Mughnetsyan, Nzar Rauf Abdullah, Chi-Shung Tang, Valeriu Moldoveanu, Andrei Manolescu
Summary: Theoretical calculations are presented for the cyclotron resonance and various magnetoplasmon modes of a two-dimensional GaAs electron gas modulated as a lateral superlattice of quantum dots under an external perpendicular constant magnetic field. Real-time excitation approach based on the Liouville-von Neumann equation for the density operator is used, which can provide information on all longitudinal and transverse collective modes of interest beyond linear response. An extensive analysis of the coexisting collective modes due to the lateral confinement and the magnetic field is performed for different number of electrons in each dot. Signs of the structure of the Hofstadter butterfly in the excitation spectra are observed in the limit of vanishing dot modulation of the two-dimensional electron gas.
