scholarly journals Magneto-Optical Transport Properties of Type-II Nodal Line Semimetals

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3035
Author(s):  
Yanmei Sun ◽  
Jing Li ◽  
Hui Zhao ◽  
Meimei Wu ◽  
Hui Pan
Keyword(s):  
Magnetic Field ◽  
Transport Properties ◽  
Polarized Light ◽  
Nodal Line ◽  
Landau Levels ◽  
Hall Conductivity ◽  
Type Ii ◽  
Circularly Polarized Light ◽  
Double Peaks ◽  
Optical Transport

We investigate the magneto-optical transport properties and Landau levels of type-II nodal line semimetals. The tilted liner dispersion in type-II nodal line semimetals makes the conduction band and valence band asymmetric, and Landau levels are coupling in the presence of a magnetic field. We find the background of absorption peaks is curved. The oscillation peaks are tailless with the change of magnetic field. Through tuning tilt term, we find the absorption peaks of optical conductivity change from incomplete degenerate structure to splitting double peaks structure. We also find interband absorption peaks is no longer zero in the imaginary part of Hall conductivity. With the change of the tilt term, the contribution of the absorption peak has two forms, one is that the negative peak only appears at high frequencies, and the other is two adjacent peaks with opposite signs. In addition, the resistivity, circularly polarized light and magnetic oscillation of Hall conductivity are studied.

Optical Pumping and Optical Detection of Spin-Polarized Electrons in a Conduction Band

1971 ◽  
Vol 49 (14) ◽  
pp. 1850-1860 ◽  
Author(s):  
R. R. Parsons
Keyword(s):  
Magnetic Field ◽  
Conduction Band ◽  
Spin Polarization ◽  
Optical Pumping ◽  
Polarized Light ◽  
Degree Of Polarization ◽  
Polarized Electrons ◽  
Excitation Light ◽  
Circularly Polarized Light ◽  
Spin Polarized

Spin-polarized electrons are created in the conduction band of p-type GaSb by excitation with σ+ or σ− circularly polarized light. The degree of polarization of the photoluminescence is used to measure the optically pumped spin polarization. The measurements as a function of transverse magnetic field yield the spin-relaxation time and the lifetime of the photocreated electrons. The degree of polarization oscillates as a function of the photon energy of the excitation light. This effect is associated with mechanisms of rapid energy loss involving optical and acoustical phonons. The optical pumping is studied as a function of temperature in the range 3.5 °K ≤ T ≤ 11 °K. A maximum spin polarization [Formula: see text] is obtained at [Formula: see text]. The efficiency of the optical pumping is significantly increased with the application of a weak longitudinal magnetic field.

A Study of Line Profiles in The Oblique Rotator Model and a Comparison with the Ap Star B Coronae Borealis.

1976 ◽  
Vol 32 ◽  
pp. 611-612
Author(s):  
R. Freedman
Keyword(s):  
Magnetic Field ◽  
Polarized Light ◽  
Line Profiles ◽  
Circularly Polarized Light ◽  
Rotator Model ◽  
Oblique Rotator ◽  
Left And Right ◽  
Effects Of Rotation ◽  
Ap Stars ◽  
The Magnetic Field

A study was made of line profiles in left and right circularly polarized light for the Ap stars βCrB. The model adopted for the surface configuration of the magnetic field was that of Wolff and Wolff (1970) who used an oblique rotator offset along the axis of the dipole field. The line profiles were calculated in pure absorption using the method of Rachovsky (1969). Allowance was made for the depth dependence of all relevant physical variables, arbitrary angles of the magnetic field, and the effect of anomalous dispersion. The elements studied were Ce II, Gd II, Mn I and Fe I. In general, weak, unsaturated lines were chosen for analysis. The final profiles were corrected for the effects of rotation.

scholarly journals MODULATION EFFECT ON SPIN HALL RESONANCE

2013 ◽  
Vol 27 (17) ◽  
pp. 1350129 ◽  
Author(s):  
SK FIROZ ISLAM
Keyword(s):  
Magnetic Field ◽  
Resonance Field ◽  
Landau Levels ◽  
Hall Conductivity ◽  
Modulation Effect ◽  
Modulation Period ◽  
Energy Correction ◽  
Electrical Modulation ◽  
Two Peaks ◽  
The Magnetic Field

The effect of a weak electrical modulation on spin Hall resonance is presented here. In presence of the magnetic field normal to the plane of the motion of electron, the Landau levels are formed which get broadened due to the weak modulation. The width of the Landau levels broadening are periodic with the inverse magnetic field. There is a certain magnetic field for which the crossing of Landau levels between spin-up and spin-down branches takes place. This gives rise to the resonance in the spin Hall conductivity (SHC). The Landau levels broadening or the energy correction due to the modulation removes the singularity which appears at the resonance field in SHC, leading to the suppression of SHC accompanied by two new peaks around this point. The separation of these two peaks increases with the increase of the modulation period. Moreover, we find that the height of the two peaks are also modulation period dependent.

Transport coefficients and Nernst signal of type-II superconductors under magnetic field

2016 ◽  
Vol 30 (03) ◽  
pp. 1550267
Author(s):  
Bui Duc Tinh ◽  
Nguyen Quang Hoc
Keyword(s):  
Magnetic Field ◽  
Electric Fields ◽  
Gaussian Approximation ◽  
Strong Electric Field ◽  
Landau Equation ◽  
Transport Coefficients ◽  
Thermal Fluctuations ◽  
Landau Levels ◽  
Type Ii ◽  
High Electric Fields

In this paper, we have studied the transport properties in two-dimensional superconductors in the frame of the Langevin approach to the time dependent Ginzburg–Landau equation. The electrical and thermoelectric conductivity, resulting from thermal fluctuations of the superconducting order parameter, are computed in the self-consistent Gaussian approximation for an arbitrarily strong electric field and a magnetic field. The Nernst signal, describing the Nernst effect in type-II superconductor under a magnetic field, is also calculated in linear response limit. We obtain analytical expressions for the electrical conductivity, the thermoelectric conductivity and the Nernst signal summing all Landau levels without need to cutoff higher Landau levels to treat an arbitrary magnetic field. Our results indicate that the electrical and thermoelectric conductivity are suppressed in high electric fields and the Nernst signal is in good agreement with experimental data on [Formula: see text].

scholarly journals Optical Transition Rates in a Cylindrical Quantum Wire with Parabolic and Inverse Parabolic Electric Confining Potentials in a Magnetic Field

2021 ◽  
Author(s):  
Moletlanyi Tshipa ◽  
Monkami Masale
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Polarized Light ◽  
Electronic States ◽  
Dipole Approximation ◽  
Transition Rates ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Quantum Numbers ◽  
Parabolic Potential

Abstract Electron transition rates due to interaction with circularly polarized light incident along the axis of a free-standing solid cylindrical nanowire are evaluated in the dipole approximation. The electric confinement potential of the nanowire is modeled as a superposition of two parts, in general, of different strengths; viz; parabolic and inverse parabolic in the radial distance. Additional confinement of the charge carriers is through the vector potential of the axial applied magnetic field. In systems with cylindrical symmetry, the electronic states are in part characterized by azimuthal quantum numbers: m=0, ±1, ±2,..., which in the absence of the axial applied magnetic field are doubly degenerate. In the dipole approximation and for circularly polarized light the selection rules are such that optical transitions are allowed between electronic states whose azimuthal quantum numbers differ by unity. Transition rates are characterized by peaks whenever the energy of the incident electromagnetic radiation matches transition energies for states between which transitions occur. The parabolic potential blue shifts peak of transition rates while the inverse parabolic potential redshifts the peaks. Results also indicate that transition rates are higher in nanowires of smaller radii. The homogeneous magnetic field lifts the double-degeneracies of electrons with opposite angular momenta, which leads to the emergence of two branches of the transition rates.

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