Results 61 to 70 of about 37,694 (310)

Periodic perturbations of Hamiltonian systems

Advances in Nonlinear Analysis, 2016
We prove existence and multiplicity results for periodic solutions of Hamiltonian systems, by the use of a higher dimensional version of the Poincaré–Birkhoff fixed point theorem.
Fonda Alessandro, Garrione Maurizio, Gidoni Paolo   +2 more
doaj   +1 more source

Microscopic Insights into Magnetic Warping and Time‐Reversal Symmetry Breaking in Topological Surface States of Rare‐Earth‐Doped Bi2Te3

Advanced Materials, EarlyView.
Magnetic doping of the topological insulator Bi2Te3 with erbium adatoms induces out‐of‐plane magnetism and breaks time‐reversal symmetry, opening a Dirac gap and driving a Fermi surface transition from hexagonal to star‐of‐David geometry. Microscopy, spectroscopy, and magnetic dichroism reveal atomically controlled magnetic interactions that tailor the
Beatriz Muñiz Cano, Fabián Calleja, Ji Dai, Massimo Tallarida, Vera Marinova, Alessandro Barla, Marc G. Cuxart, Pierluigi Gargiani, Gonzalo N. Molina, José Angel Silva‐Guillén, Adriana I. Figueroa, Kevin García‐Díez, Sergio O. Valenzuela, Aitor Mugarza, Amadeo L. Vázquez de Parga, Rodolfo Miranda, Francisco Guinea, Manuela Garnica, Miguel A. Valbuena   +18 more
wiley   +1 more source

Self‐Cooling Molecular Spin Qudits

Advanced Materials, EarlyView.
A material made of [GdEr] molecular dimers can encode a qudit and perform as a magnetic refrigerant. Microwave resonant pulses coherently manipulate its 16 spin states, while direct demagnetization measurements cool the material and a device down to temperatures below 1 K.
Elías Palacios, David Aguilà, David Gracia, Diamatoula Maniaki, Leoní A. Barrios, Alessandro Chiesa, Jesús I. Martínez, Valentin Novikov, Olivier Roubeau, Stefano Carretta, Marco Evangelisti, Guillem Aromí, Fernando Luis   +12 more
wiley   +1 more source

Polyimide‐Linked Hexaazatriphenylene‐Based Porous Organic Polymer with Multiple Redox‐Active Sites as a High‐Capacity Organic Cathode for Lithium‐Ion Batteries

Advanced Materials, EarlyView.
A high‐capacity polyimide‐linked porous organic polymer (HAT‐PTO) incorporating numerous redox‐active centers is synthesized via a hydrothermal reaction, delivering a high theoretical capacity of 484 mAh g−1. In situ hybridization with carboxyl‐functionalized multiwalled carbon nanotubes enhances conductivity and stability, achieving 397 mAh g−1 at C ...
Arindam Mal, Jonathan Caroni, Asia Patriarchi, Olivera Luzanin, Rafael Ramos, Jan Bitenc, Manuel Melle‐Franco, Manuel Souto   +7 more
wiley   +1 more source

Periodic solutions for a class of second-order Hamiltonian systems of prescribed energy

Electronic Journal of Qualitative Theory of Differential Equations, 2015
In this paper, the existence of non-constant periodic solutions for a class of conservative Hamiltonian systems with prescribed energy is obtained by the saddle point theorem.
Dong-Lun Wu, Chun Li, Pengfei Yuan
doaj   +1 more source

High Charge Carrier Mobility in Non‐Conjugated 3D Covalent Organic Frameworks

Advanced Materials, EarlyView.
A non‐conjugated 3D COF constructed via boronate ester linkages from tetraphenylene and pyrene‐based monomers is reported, which exhibits a high charge carrier mobility of 14 ± 1 cm2 V−1 s−1. ABSTRACT π‐Conjugation, π–π stacking, and long‐range order play a central role in determining charge transport efficiency in organic materials.
Joaquín Almarza, Karol Strutyński, Shuai Fu, Yifan Chen, Natalia M. Padial, Isabel del Barrio Gómez, Carlos Martí‐Gastaldo, Andrei N. Khlobystov, Mischa Bonn, Hai I. Wang, Manuel Melle‐Franco, Aurelio Mateo‐Alonso   +11 more
wiley   +1 more source

Gapless Superconductivity From Extremely Dilute Magnetic Disorder in 2H‐NbSe2‐xSx

Advanced Materials, EarlyView.
We demonstrate that 2H‐NbSe2‐xSx hosts gapless superconductivity at unexpectedly low magnetic impurity concentrations. Combining STM, Bogoliubovde Gennes simulations, DFT, and quasiparticle interference, we comprehensively study the development of gapless behavior and show that SeS substitution reshapes the band structure, enhances nesting, and drives ...
Jose Antonio Moreno, Mercè Roig, Víctor Barrena, Edwin Herrera, Alberto M. Ruiz, Samuel Mañas‐Valero, Antón Fente, Anita Smeets, Jazmín Aragón, Yanina Fasano, Beilun Wu, Maria N. Gastiasoro, Eugenio Coronado, José J. Baldoví, Brian M. Andersen, Isabel Guillamón, Hermann Suderow   +16 more
wiley   +1 more source

The Multiplicity Problem for Periodic Orbits of Magnetic Flows on the 2-Sphere

Advanced Nonlinear Studies, 2017
We consider magnetic Tonelli Hamiltonian systems on the cotangent bundle of the 2-sphere, where the magnetic form is not necessarily exact. It is known that, on very low and on high energy levels, these systems may have only finitely many periodic orbits.
Abbondandolo Alberto, Asselle Luca, Benedetti Gabriele, Mazzucchelli Marco, Taimanov Iskander A.   +4 more
doaj   +1 more source

Thermal‐Driven Diode Polarity Switching From Competing Helical Superconducting States in WTe2/α‐Fe2O3 Heterostructures

Advanced Materials, EarlyView.
A Nb‐proximitized Josephson junction based on a WTe2/α‐Fe2O3 heterostructure exhibits a robust superconducting diode effect with programmable polarity. The diode direction can be trained by magnetic fields and switched by temperature cycling, revealing tunable finite‐momentum pairing states and competing superconducting states in symmetry‐broken ...
Enze Zhang, Grant Z. X. Yang, Zi‐Ting Sun, Xinhou Chen, Shishun Zhao, Chufan Chen, Chenhui Zhang, Fanrui Hu, K. T. Law, Hyunsoo Yang   +9 more
wiley   +1 more source

NORMALIZATION OF CLASSICAL HAMILTONIAN SYSTEMS WITH TWO DEGREES OF FREEDOM

Физико-химические аспекты изучения кластеров, наноструктур и наноматериалов, 2020
The family of the Hamiltonian systems with two degrees of freedom was investigated. The calculations of the Poincaré sections show that with arbitrary values of the parameters of the Hamilton function, the system is non-integrable and dynamic chaos is ...
I.N. Belyaeva, I.K. Kirichenko, O.D. Ptashnyi, N.N. Chekanova, T.A. Yarkho   +4 more
doaj   +1 more source