Optical signatures of Dirac nodal lines in NbAs2

Using polarized optical and magneto-optical spectroscopy, we have demonstrated universal aspects of electrodynamics associated with Dirac nodal lines that are found in several classes of unconventional intermetallic compounds. We investigated anisotropic electrodynamics of NbAs2 where the spin-orbit coupling (SOC) triggers energy gaps along the nodal lines. These gaps manifest as sharp steps in the optical conductivity spectra σ1(ω). This behavior is followed by the linear power-law scaling of σ1(ω) at higher frequencies, consistent with our theoretical analysis for dispersive Dirac nodal lines. Magneto-optics data affirm the dominant role of nodal lines in the electrodynamics of NbAs2.

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Manipulation of the Rashba spin-orbit coupling of a distorted 1T-phase Janus WSSe monolayer: Dominant role of charge transfer and orbital components

Physical Review B ◽

10.1103/physrevb.103.195114 ◽

2021 ◽

Vol 103 (19) ◽

Author(s):

Wenzhe Zhou ◽

Jianyong Chen ◽

Bei Zhang ◽

Haiming Duan ◽

Fangping Ouyang

Keyword(s):

Charge Transfer ◽

Dominant Role ◽

Orbit Coupling ◽

Spin Orbit Coupling ◽

Spin Orbit ◽

Rashba Spin

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THE ROLE OF SPIN-ORBIT COUPLING AND HYPERFINE COUPLING IN OPTICAL PUMPING OF F-CENTRES

Le Journal de Physique Colloques ◽

10.1051/jphyscol:1976718 ◽

1976 ◽

Vol 37 (C7) ◽

pp. C7-104-C7-104

Author(s):

K. E. MAUSER ◽

B. NIESERT ◽

A. WINNACKER

Keyword(s):

Hyperfine Coupling ◽

Optical Pumping ◽

Orbit Coupling ◽

Spin Orbit Coupling ◽

Spin Orbit

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Clustering-Triggered Efficient Room Temperature Phosphorescence from Nonconventional Luminophores

10.26434/chemrxiv.9959132 ◽

2019 ◽

Author(s):

Shuyuan Zheng ◽

Taiping Hu ◽

Xin Bin ◽

Yunzhong Wang ◽

Yuanping Yi ◽

...

Keyword(s):

Room Temperature ◽

High Efficiency ◽

Spin Orbit Coupling ◽

Design Rationale ◽

Emission Mechanism ◽

Room Temperature Phosphorescence ◽

Electronic Interactions ◽

Energy Gaps ◽

Theoretical Results

Pure organic room temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Here we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boost the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5% is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results would spur the future fabrication of nonconventional phosphors, and moreover should advance understanding of the underlying emission mechanism.<br>

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Dzyaloshinskii–Moriya interaction in noncentrosymmetric superlattices

npj Computational Materials ◽

10.1038/s41524-021-00592-8 ◽

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.

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Low-Energy Optical Conductivity of TaP: Comparison of Theory and Experiment

Crystals ◽

10.3390/cryst11050567 ◽

2021 ◽

Vol 11 (5) ◽

pp. 567

Author(s):

Alexander Yaresko ◽

Artem V. Pronin

Keyword(s):

Experimental Data ◽

Optical Conductivity ◽

Low Energy ◽

Spin Orbit Coupling ◽

Spin Orbit ◽

Natural Explanation ◽

Weyl Semimetal ◽

Unintentional Doping ◽

Mott Formula ◽

Theory And Experiment

The ab-plane optical conductivity of the Weyl semimetal TaP is calculated from the band structure and compared to the experimental data. The overall agreement between theory and experiment is found to be best when the Fermi level is slightly (20 to 60 meV) shifted upwards in the calculations. This confirms a small unintentional doping of TaP, reported earlier, and allows a natural explanation of the strong low-energy (50 meV) peak seen in the experimental ab-plane optical conductivity: this peak originates from transitions between the almost parallel non-degenerate electronic bands split by spin-orbit coupling. The temperature evolution of the peak can be reasonably well reproduce by calculations using an analog of the Mott formula.

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