scholarly journals Bandgap bowing in a zero-dimensional hybrid halide perovskite derivative: spin–orbit coupling versus lattice strain

2020 ◽  
Vol 8 (8) ◽  
pp. 4416-4427 ◽  
Author(s):  
Soumyo Chatterjee ◽  
Julia Payne ◽  
John T. S. Irvine ◽  
Amlan J. Pal
Keyword(s):  
Lattice Strain ◽  
Orbit Coupling ◽  
Lead Free ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Isovalent Substitution ◽  
Halide Perovskite

The bandgap bowing phenomenon has been observed in lead-free MA3Sb2I9 perovskite upon isovalent substitution by bismuth (Bi3+).

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.

Spin–orbit coupling driven novel magnetism in d 5 6H-perovskite iridates Ba3IrTi2O9 and Ba3TiIr2O9

2019 ◽  
Vol 31 (18) ◽  
pp. 185802 ◽  
Author(s):  
Sayantika Bhowal ◽  
Shreemoyee Ganguly ◽  
Indra Dasgupta
Keyword(s):  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit

scholarly journals Dzyaloshinskii–Moriya interaction in noncentrosymmetric superlattices

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Woo Seung Ham ◽  
Abdul-Muizz Pradipto ◽  
Kay Yakushiji ◽  
Kwangsu Kim ◽  
Sonny H. Rhim ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Degrees Of Freedom ◽  
Orbit Coupling ◽  
Inversion Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Band Formation ◽  
Research Activities ◽  
Moriya Interaction

AbstractDzyaloshinskii–Moriya interaction (DMI) is considered as one of the most important energies for specific chiral textures such as magnetic skyrmions. The keys of generating DMI are the absence of structural inversion symmetry and exchange energy with spin–orbit coupling. Therefore, a vast majority of research activities about DMI are mainly limited to heavy metal/ferromagnet bilayer systems, only focusing on their interfaces. Here, we report an asymmetric band formation in a superlattices (SL) which arises from inversion symmetry breaking in stacking order of atomic layers, implying the role of bulk-like contribution. Such bulk DMI is more than 300% larger than simple sum of interfacial contribution. Moreover, the asymmetric band is largely affected by strong spin–orbit coupling, showing crucial role of a heavy metal even in the non-interfacial origin of DMI. Our work provides more degrees of freedom to design chiral magnets for spintronics applications.

scholarly journals Recent advances in tunable spin–orbit coupling using ferroelectricity

APL Materials ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 060704
Author(s):  
Mei Fang ◽  
Wenchao Zhang ◽  
Xiaoyu Wu ◽  
Wang Guo ◽  
Huayan Xia ◽  
...  
Keyword(s):  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Recent Advances
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