scholarly journals Evolution of Spin-Orbital Entanglement with Increasing Ising Spin-Orbit Coupling

2020 ◽  
Vol 5 (3) ◽  
pp. 53
Author(s):  
Dorota Gotfryd ◽  
Ekaterina Pärschke ◽  
Krzysztof Wohlfeld ◽  
Andrzej M. Oleś
Keyword(s):  
Quantum Entanglement ◽  
Transition Metal Oxides ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Spin Orbital ◽  
Ising Spin ◽  
Quantum Matter ◽  
Effective Models ◽  
Strong Spin

Several realistic spin-orbital models for transition metal oxides go beyond the classical expectations and could be understood only by employing the quantum entanglement. Experiments on these materials confirm that spin-orbital entanglement has measurable consequences. Here, we capture the essential features of spin-orbital entanglement in complex quantum matter utilizing 1D spin-orbital model which accommodates SU(2)⊗SU(2) symmetric Kugel-Khomskii superexchange as well as the Ising on-site spin-orbit coupling. Building on the results obtained for full and effective models in the regime of strong spin-orbit coupling, we address the question whether the entanglement found on superexchange bonds always increases when the Ising spin-orbit coupling is added. We show that (i) quantum entanglement is amplified by strong spin-orbit coupling and, surprisingly, (ii) almost classical disentangled states are possible. We complete the latter case by analyzing how the entanglement existing for intermediate values of spin-orbit coupling can disappear for higher values of this coupling.

scholarly journals Observation of chiral surface excitons in a topological insulator Bi2Se3

2019 ◽  
Vol 116 (10) ◽  
pp. 4006-4011 ◽  
Author(s):  
H.-H. Kung ◽  
A. P. Goyal ◽  
D. L. Maslov ◽  
X. Wang ◽  
A. Lee ◽  
...  
Keyword(s):  
Polarized Light ◽  
Orbit Coupling ◽  
Experimental Investigations ◽  
Composite Particles ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Excitation Energies ◽  
Circularly Polarized Light ◽  
Pl Emission ◽  
Strong Spin

The protected electron states at the boundaries or on the surfaces of topological insulators (TIs) have been the subject of intense theoretical and experimental investigations. Such states are enforced by very strong spin–orbit interaction in solids composed of heavy elements. Here, we study the composite particles—chiral excitons—formed by the Coulomb attraction between electrons and holes residing on the surface of an archetypical 3D TI,Bi2Se3. Photoluminescence (PL) emission arising due to recombination of excitons in conventional semiconductors is usually unpolarized because of scattering by phonons and other degrees of freedom during exciton thermalization. On the contrary, we observe almost perfectly polarization-preserving PL emission from chiral excitons. We demonstrate that the chiral excitons can be optically oriented with circularly polarized light in a broad range of excitation energies, even when the latter deviate from the (apparent) optical band gap by hundreds of millielectronvolts, and that the orientation remains preserved even at room temperature. Based on the dependences of the PL spectra on the energy and polarization of incident photons, we propose that chiral excitons are made from massive holes and massless (Dirac) electrons, both with chiral spin textures enforced by strong spin–orbit coupling. A theoretical model based on this proposal describes quantitatively the experimental observations. The optical orientation of composite particles, the chiral excitons, emerges as a general result of strong spin–orbit coupling in a 2D electron system. Our findings can potentially expand applications of TIs in photonics and optoelectronics.

scholarly journals Quantum materials with strong spin-orbit coupling: challenges and opportunities for materials chemists

2021 ◽  
Author(s):  
Alexander J. Browne ◽  
Aleksandra Krajewska ◽  
Alexandra Gibbs
Keyword(s):  
Transition Metals ◽  
Quantum Effect ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Challenges And Opportunities ◽  
Quantum Materials ◽  
Magnetic States ◽  
Strong Spin

Spin-orbit coupling is a quantum effect that can give rise to exotic electronic and magnetic states in the compounds of the 4d and 5d transition metals. Exploratory synthesis, chemical tuning...

scholarly journals How spin-orbital entanglement depends on the spin-orbit coupling in a Mott insulator

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Dorota Gotfryd ◽  
Ekaterina M. Pärschke ◽  
Jiří Chaloupka ◽  
Andrzej M. Oleś ◽  
Krzysztof Wohlfeld
Keyword(s):  
Mott Insulator ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Spin Orbital

scholarly journals Observation of quantum interference conductance fluctuations in metal rings with strong spin–orbit coupling

2020 ◽  
Vol 117 (24) ◽  
pp. 242402
Author(s):  
R. Ramos ◽  
T. Makiuchi ◽  
T. Kikkawa ◽  
S. Daimon ◽  
K. Oyanagi ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Metal Rings ◽  
Conductance Fluctuations ◽  
Strong Spin
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