Effect of a magnetic field on anE⊗εJahn-Teller system: Berry phase and optical properties

2001 ◽  
Vol 63 (13) ◽  
Author(s):  
G. Bevilacqua ◽  
L. Martinelli ◽  
G. Pastori Parravicini
Keyword(s):  
Magnetic Field ◽  
Optical Properties ◽  
Berry Phase

MAGNETIC FIELD, PRESSURE AND TEMPERATURE DEPENDENT OPTICAL PROPERTIES IN A GaAs 9.0 P 1.0 QUANTUM DOT

2014 ◽  
Vol 6 (2) ◽  
pp. 1178-1190
Author(s):  
A. JOHN PETER ◽  
Ada Vinolin
Keyword(s):  
Magnetic Field ◽  
Optical Properties ◽  
Quantum Dot ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Photon Energy ◽  
Nonlinear Optical ◽  
Binding Energies ◽  
Nonlinear Optical Properties ◽  
Optical Rectification

Simultaneous effects of magnetic field, pressure and temperature on the exciton binding energies are found in a 9.0 1.0 6.0 4.0 GaAs P / GaAs P quantum dot. Numerical calculations are carried out taking into consideration of spatial confinement effect. The cylindrical system is taken in the present problem with the strain effects. The electronic properties and the optical properties are found with the combined effects of magnetic field strength, hydrostatic pressure and temperature values. The exciton binding energies and the nonlinear optical properties are carried out taking into consideration of geometrical confinement and the external perturbations.Compact density approach is employed to obtain the nonlinear optical properties. The optical rectification coefficient is obtained with the photon energy in the presence of pressure, temperature and external magnetic field strength. Pressure and temperature dependence on nonlinear optical susceptibilities of generation of second and third order harmonics as a function of incident photon energy are brought out in the influence of magnetic field strength. The result shows that the electronic and nonlinear optical properties are significantly modified by the applications of external perturbations in a 9.0 1.0 6.0 4.0 GaAs P / GaAs P quantum dot.

scholarly journals Giant magnetic field from moiré induced Berry phase in homobilayer semiconductors

2019 ◽  
Vol 7 (1) ◽  
pp. 12-20 ◽  
Author(s):  
Hongyi Yu ◽  
Mingxing Chen ◽  
Wang Yao
Keyword(s):  
Magnetic Field ◽  
Berry Phase ◽  
Transition Metal Dichalcogenides ◽  
Real Space ◽  
Quantum Spin ◽  
Moire Patterns ◽  
Metal Dichalcogenides ◽  
Berry Phases ◽  
Different Origins ◽  
Moiré Patterns

Abstract When quasiparticles move in condensed matters, the texture of their internal quantum structure as a function of position and momentum can give rise to Berry phases that have profound effects on the material’s properties. Seminal examples include the anomalous Hall and spin Hall effects from the momentum-space Berry phases in homogeneous crystals. Here, we explore a conjugate form of the electron Berry phase arising from the moiré pattern: the texture of atomic configurations in real space. In homobilayer transition metal dichalcogenides, we show that the real-space Berry phase from moiré patterns manifests as a periodic magnetic field with magnitudes of up to hundreds of Tesla. This quantity distinguishes moiré patterns from different origins, which can have an identical potential landscape, but opposite quantized magnetic flux per supercell. For low-energy carriers, the homobilayer moirés realize topological flux lattices for the quantum-spin Hall effect. An interlayer bias can continuously tune the spatial profile of the moiré magnetic field, whereas the flux per supercell is a topological quantity that can only have a quantized jump observable at a moderate bias. We also reveal the important role of the non-Abelian Berry phase in shaping the energy landscape in small moiré patterns. Our work points to new possibilities to access ultra-high magnetic fields that can be tailored to the nanoscale by electrical and mechanical controls.

Metamaterials from Amorphous Ferromagnetic Microwires: Interaction between Microwires

2009 ◽  
Vol 152-153 ◽  
pp. 357-360 ◽  
Author(s):  
Andrei V. Ivanov ◽  
A.N. Shalygin ◽  
V.Yu. Galkin ◽  
A.V. Vedyayev ◽  
V.A. Ivanov
Keyword(s):  
Magnetic Field ◽  
Refractive Index ◽  
Optical Properties ◽  
External Magnetic Field ◽  
Electromagnetic Waves ◽  
Negative Refractive Index ◽  
Magnus Effect ◽  
Amorphous Ferromagnet ◽  
Wide Scale ◽  
Optical Magnus Effect

For inhomogeneous mediums the оptical Magnus effect has been derived. The metamaterials fabricated from amorphous ferromagnet Co-Fe-Cr-B-Si microwires are shown to exhibit a negative refractive index for electromagnetic waves over wide scale of GHz frequencies. Optical properties and optical Magnus effect of such metamaterials are tunable by an external magnetic field.

Study on Photodynamic Therapy for HL60 Cells Inactivation by Visible Light-Induced Fe-Doped Nano-TiO2 under Magnetic Field

2010 ◽  
Vol 152-153 ◽  
pp. 136-143
Author(s):  
Yu Ying Xiong ◽  
Cui Fen Liang ◽  
Hua Xiao ◽  
Jian Wen Xiong
Keyword(s):  
Magnetic Field ◽  
Optical Properties ◽  
Photodynamic Therapy ◽  
Leukemic Cells ◽  
Precipitation Method ◽  
Doping Content ◽  
Fe Doping ◽  
Nano Tio2 ◽  
Doped Tio2 ◽  
Tio2 Particles

Fe-doped TiO2 was prepared by a homogenous precipitation method and characterized by XRD, UV-Vis DRS. The structure and the optical properties of nano-TiO2 with different Fe doping content were studied, as well as the effect and the possible mechanics of different intensity of TiO2 particles, Fe-doped nano-TiO2 particles on the activity of HL60 leukemic cells. The influence on the activity of cells exposures in light compared with un-exposure also be analysed. As the photo sensitizers, TiO2 and Fe-doped TiO2 particles eliminated tumor cell using photodynamic therapy(PDT)under magnetic field.

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