Non-thermal optical excitation of terahertz-spin precession in a magneto-optical insulator

2016 ◽  
Vol 108 (3) ◽  
pp. 032404 ◽  
Author(s):  
Sergii Parchenko ◽  
Takuya Satoh ◽  
Isao Yoshimine ◽  
Feliks Stobiecki ◽  
Andrzej Maziewski ◽  
...  
Keyword(s):  
Optical Excitation ◽  
Spin Precession ◽  
Optical Insulator

scholarly journals Dynamics of Magnetization in Multilayer TbCo / FeCo Structures under the Influence of Femtosecond Optical Excitation

2019 ◽  
Vol 7 (3) ◽  
pp. 50-58 ◽  
Author(s):  
N. A. Ilyin ◽  
A. A. Klimov ◽  
N. Tiercelin ◽  
P. Pernod ◽  
E. D. Mishina ◽  
...  
Keyword(s):  
Easy Axis ◽  
Uniaxial Anisotropy ◽  
Anisotropy Field ◽  
Optical Excitation ◽  
Spin Precession ◽  
Heat Diffusion ◽  
Easy Magnetization ◽  
Test Beam ◽  
Magnetic Subsystem ◽  
Hard Axis

The need to study ultrafast processes in magnetism is due to the prospects for creating ultrafast magnetic recording and ultrafast spintronic devices. In order to excite the magnetic subsystem femtosecond optical pulses are used. The excitement is manifested as in spin precession. In metals, the material is heated first due to significant optical absorption, and significant Joule losses occur. The most important task is to search for materials in which spin processes are excited without heating. Obvious candidates are weakly absorbing materials, such as ferrite garnets. However, the range of such materials and the range of their functionality are limited.The purpose of this work is to study the dynamics of systems with nonthermal mechanisms of spin precession excitation. Such excitation is possible in ferromagnetic / antiferromagnetic heterostructures with exchange interaction, provided that the recombination time of photocarriers is shorter than the time of heat diffusion. Multilayer TbCo / FeCo structures of the near IR range were investigated for a femtosecond optical pulse. The spin dynamics are compared with the direction of the wave vector of the exciting pulse along and perpendicular to the axis of easy magnetization of the structures (“easy axis” and “hard axis” geometry, respectively). It is shown that in case of “easy axis” geometry the determinative mechanism is the thermal interaction. When the system is exposed to an excitation pulse, this mechanism leads to a decrease in the projection of magnetization on the direction of propagation of the test beam. In case of “hard axis” geometry, the magnetization turns to the magnetic field at the initial stage. Then it precesses and relaxes to an equilibrium angular orientation. Such dynamics indicate a rapid recovery of the uniaxial anisotropy field after laser irradiation. The presented results demonstrate an ultrafast change in the magnetic anisotropy induced during the fabrication of the heterostructure under study, which may be of interest for optical control of the orientation of the magnetization.

LOW ENERGY OPTICAL EXCITATION IN CeB6

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-737-C8-738
Author(s):  
Y. S. Kwon ◽  
S. Kimura ◽  
T. Nanba ◽  
S. Kunii ◽  
M. Ikezawa ◽  
...  
Keyword(s):  
Optical Excitation ◽  
Low Energy

SPIN PRECESSION AND PHASE DELAY TUNNELING TIMES

1988 ◽  
Vol 49 (C6) ◽  
pp. C6-17-C6-22 ◽  
Author(s):  
Z. HUANG ◽  
P. H. CUTLER ◽  
T. E. FEUCHTWANG ◽  
R. H. GOOD ◽  
Jr. ◽  
...  
Keyword(s):  
Phase Delay ◽  
Spin Precession ◽  
Tunneling Times

Anti-Stokes Luminescence of Bulk and Thin-Film β-InSe under Infrared Optical Excitation

JETP Letters ◽  
2020 ◽  
Vol 112 (3) ◽  
pp. 145-149
Author(s):  
S. N. Nikolaev ◽  
M. A. Chernopitsskii ◽  
V. S. Bagaev ◽  
V. S. Krivobok
Keyword(s):  
Thin Film ◽  
Optical Excitation ◽  
Anti Stokes

Semiconductors

2018 ◽  
Author(s):  
L. Solymar ◽  
D. Walsh ◽  
R. R. A. Syms
Keyword(s):  
Crystal Growth ◽  
Molecular Beam ◽  
Vapour Deposition ◽  
Energy Levels ◽  
Chemical Vapour ◽  
Optical Excitation ◽  
Organic Chemical ◽  
Metal Organic ◽  
Mathematical Relations ◽  
Semiconductor Properties

Both intrinsic and extrinsic semiconductors are discussed in terms of their band structure. The acceptor and donor energy levels are introduced. Scattering is discussed, from which the conductivity of semiconductors is derived. Some mathematical relations between electron and hole densities are derived. The mobilities of III–V and II–VI compounds and their dependence on impurity concentrations are discussed. Band structures of real and idealized semiconductors are contrasted. Measurements of semiconductor properties are reviewed. Various possibilities for optical excitation of electrons are discussed. The technology of crystal growth and purification are reviewed, in particular, molecular beam epitaxy and metal-organic chemical vapour deposition.

scholarly journals Creation of Negatively Charged Boron Vacancies in Hexagonal Boron Nitride Crystal by Electron Irradiation and Mechanism of Inhomogeneous Broadening of Boron Vacancy-Related Spin Resonance Lines

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1373
Author(s):  
Fadis F. Murzakhanov ◽  
Boris V. Yavkin ◽  
Georgiy V. Mamin ◽  
Sergei B. Orlinskii ◽  
Ivan E. Mumdzhi ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Electron Irradiation ◽  
Near Infrared ◽  
Hexagonal Boron Nitride ◽  
Optical Excitation ◽  
High Energy ◽  
Infrared Range ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Spin Resonance

Optically addressable high-spin states (S ≥ 1) of defects in semiconductors are the basis for the development of solid-state quantum technologies. Recently, one such defect has been found in hexagonal boron nitride (hBN) and identified as a negatively charged boron vacancy (VB−). To explore and utilize the properties of this defect, one needs to design a robust way for its creation in an hBN crystal. We investigate the possibility of creating VB− centers in an hBN single crystal by means of irradiation with a high-energy (E = 2 MeV) electron flux. Optical excitation of the irradiated sample induces fluorescence in the near-infrared range together with the electron spin resonance (ESR) spectrum of the triplet centers with a zero-field splitting value of D = 3.6 GHz, manifesting an optically induced population inversion of the ground state spin sublevels. These observations are the signatures of the VB− centers and demonstrate that electron irradiation can be reliably used to create these centers in hBN. Exploration of the VB− spin resonance line shape allowed us to establish the source of the line broadening, which occurs due to the slight deviation in orientation of the two-dimensional B-N atomic plains being exactly parallel relative to each other. The results of the analysis of the broadening mechanism can be used for the crystalline quality control of the 2D materials, using the VB− spin embedded in the hBN as a probe.

scholarly journals Fine structures of valley-polarized excitonic states in monolayer transitional metal dichalcogenides

Nanophotonics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1811-1829 ◽  
Author(s):  
Zhipeng Li ◽  
Tianmeng Wang ◽  
Shengnan Miao ◽  
Zhen Lian ◽  
Su-Fei Shi
Keyword(s):  
Optical Excitation ◽  
Coherence Time ◽  
Two Dimensions ◽  
Degree Of Freedom ◽  
Research Progress ◽  
Many Body ◽  
Transitional Metal ◽  
Metal Dichalcogenides ◽  
Fine Structures ◽  
Excitonic States

AbstractMonolayer transitional metal dichalcogenides (TMDCs), a new class of atomically thin semiconductor, respond to optical excitation strongly with robust excitons, which stem from the reduced screening in two dimensions. These excitons also possess a new quantum degree of freedom known as valley spin, which has inspired the field of valleytronics. The strongly enhanced Coulomb interaction allows the exciton to bind with other particles to form new excitonic states. However, despite the discovery of trions, most of the excitonic states in monolayer TMDCs remain elusive until recently, when new light was shed into the fascinating excitonic fine structures with drastically improved sample quality through boron nitride encapsulation. Here, we review the latest research progress on fine structures of excitonic states in monolayer TMDCs, with a focus on tungsten-based TMDCs and related alloy. Many of the new excitonic complexes inherit the valley degree of freedom, and the valley-polarized dark excitonic states are of particular interest because of their long lifetime and possible long valley coherence time. The capability of resolving the excitonic fine structures also enables the investigation of exciton–phonon interactions. The knowledge of the interlayer between excitons and other particles not only advances our understanding of many-body effects in the monolayer TMDCs but also provides guidance on future applications based on TMDCs.

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