scholarly journals Field-Angle Dependence of Interlayer Magnetoresistance in Organic Dirac Electron System α-(BEDT-TTF)2I3

Crystals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 212 ◽  
Author(s):  
Takehiro Tani ◽  
Naoya Tajima ◽  
Akito Kobayashi
Keyword(s):  
Magnetic Field ◽  
Coulomb Interaction ◽  
Electron System ◽  
Landau Levels ◽  
Spin Splitting ◽  
Organic Conductor ◽  
Angle Dependence ◽  
Dirac Electron ◽  
The Magnetic Field ◽  
Theory And Experiments

The effect of the Coulomb interaction in interlayer magnetoresistance is elucidated in collaboration with theory and experiments for the Dirac electron system in organic conductor α -(BEDT-TTF) 2 I 3 under a strong magnetic field. It is found that the effective g-factor enhanced by Coulomb interaction depends on the angle of the magnetic field, resulting in the field-angle dependence of a characteristic magnetic field in which interlayer resistance has a minimum due to spin splitting N = 0 Landau levels. The qualitative agreement between the theory and experimental results for the field-angle dependence of interlayer magnetoresistance is obtained.

MATHEMATICAL MODELING OF TEMPERATURE EFFECT ON THE FAN CHART OF MAGNETOABSORPTION SPECTRUM IN SEMICONDUCTORS

2019 ◽  
pp. 104-115
Author(s):  
G. Gulyamov ◽  
U. I. Erkaboev ◽  
A. G. Gulyamov
Keyword(s):  
Mathematical Modeling ◽  
Magnetic Field ◽  
Temperature Dependence ◽  
Density Of States ◽  
Landau Levels ◽  
Joint Density ◽  
Narrow Gap ◽  
Narrow Gap Semiconductors ◽  
Dispersion Law ◽  
The Magnetic Field

The article considers the oscillations of interband magneto-optical absorption in semiconductors with the Kane dispersion law. We have compared the changes in oscillations of the joint density of states with respect to the photon energy for different Landau levels in parabolic and non-parabolic zones. An analytical expression is obtained for the oscillation of the combined density of states in narrow-gap semiconductors. We have calculated the dependence of the maximum photon energy on the magnetic field at different temperatures. A theoretical study of the band structure showed that the magnetoabsorption oscillations decrease with an increase in temperature, and the photon energies nonlinearly depend on a strong magnetic field. The article proposes a simple method for calculating the oscillation of joint density of states in a quantizing magnetic field with the non-quadratic dispersion law. The temperature dependence of the oscillations joint density of states in semiconductors with non-parabolic dispersion law is obtained. Moreover, the article studies the temperature dependence of the band gap in a strong magnetic field with the non-quadratic dispersion law. The method is applied to the research of the magnetic absorption in narrow-gap semiconductors with nonparabolic dispersion law. It is shown that as the temperature increases, Landau levels are washed away due to thermal broadening and density of states turns into a density of states without a magnetic field. Using the mathematical model, the temperature dependence of the density distribution of energy states in strong magnetic fields is considered. It is shown that the continuous spectrum of the density of states, measured at the temperature of liquid nitrogen, at low temperatures turns into discrete Landau levels. Mathematical modeling of processes using experimental values of the continuous spectrum of the density of states makes it possible to calculate discrete Landau levels. We have created the three-dimensional fan chart of magneto optical oscillations of semiconductors with considering for the joint density of energy states. For a nonquadratic dispersion law, the maximum frequency of the absorbed light and the width of the forbidden band are shown to depend nonlinearly on the magnetic field. Modeling the temperature  dependence allowed us to determine the Landau levels in semiconductors in a wide temperature spectrum. Using the proposed model, the experimental results obtained for narrow-gap semiconductors are analyzed. The theoretical results are compared with experimental results.

THE STUDY OF THE MAGNETIC BREAKDOWN EFFECT AS A FUNCTION OF ANGLE IN THE ORGANIC CONDUCTOR K- (BEDT-TTF)2Cu(NCS)2 IN HIGH MAGNETIC FIELDS

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3355-3359
Author(s):  
I. MIHUT ◽  
C. C. AGOSTA ◽  
C. H. MIELKE ◽  
M. TOKOMOTO
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Spin Splitting ◽  
High Magnetic Fields ◽  
Organic Conductor ◽  
Cross Sectional ◽  
Tank Circuit ◽  
Quantum Oscillations ◽  
Magnetic Breakdown ◽  
Splitting Factor

The magnetic breakdown effect can be seen by the growth of new frequencies in the quantum oscillations in clean metals as a function of magnetic field. We have studied the variation of the amplitudes in the quantum oscillations in the resistance (the Shubnikov-de Haas effect) as a function of angle in the quasi-two dimensional-organic conductor κ-(BEDT-TTF)2Cu(NCS)2. The measurements were made by means of a radio frequency (rf) tank circuit (~ 50 MHz) at very high magnetic fields(50T-60T) and low temperature(500 mK). The geometry of the rf excitation we used excited in-plane currents, and therefore we measured the in-plane resistivity. In contrast to conventional transport measurements that measure the inter-plane resistivity, the in-plane resistivity is dominated by the magnetic breakdown frequencies. As a result we measured much higher breakdown frequency amplitudes than conventional transport experiments. As is expected, the angular dependence of the Shubnikov-de Haas frequencies have a 1/cosθ behavior. This is due to the change of the cross sectional area of the tubular Fermi surface as the angle with respect to the magnetic field is changed. The amplitude of the oscillations changes due to the spin splitting factor which takes into account the ratio between the spin splitting and the energy spacing of the Landau levels which also has 1/cosθ behavior. We show that our data agree with the semi-classical theory (Lifshitz-Kosevich formula).

High magnetic field NMR investigation of the spin density wave phase of TMTSF2PF6

2002 ◽  
Vol 12 (9) ◽  
pp. 389-389
Author(s):  
W. G. Clark ◽  
F. Zamborsky ◽  
B. Alavi ◽  
P. Vonlanthen ◽  
W. Moulton ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Spin Density ◽  
Density Wave ◽  
Spin Density Wave ◽  
Proton Relaxation ◽  
High Magnetic Fields ◽  
Organic Conductor ◽  
First Order ◽  
The Magnetic Field ◽  
Very High

We report proton NMR measurements of the effect of very high magnetic fields up to 44.7 T (1.9 GHz) on the spin density wave (SDW) transition of the organic conductor TMTSF2PF6. Up to 1.8 GHz, no effect of critical slowing close to the transition is seen on the proton relaxation rate (1/T1), which is determined by the SDW fluctuations associated with the phase transition at the NMR frequency. Thus, the correlation time for such fluctuations is less than $1O^{-10}$s. A possible explanation for the absence of longer correlation times is that the transition is weakly first order, so that the full critical divergence is never achieved. The measurements also show a dependence of the transition temperature on the orientation of the magnetic field and a quadratic dependence on its magnitude that agrees with earlier transport measurements at lower fields. The UCLA part of this work was supported by NSF Grant DMR-0072524.

Oscillatory non-resonant interband Faraday rotation in InSb and PbTe—a new magneto-optical effect

1971 ◽  
Vol 321 (1546) ◽  
pp. 303-320 ◽  
Keyword(s):  
Magnetic Field ◽  
Conduction Band ◽  
Field Dependence ◽  
Faraday Rotation ◽  
Magnetic Field Dependence ◽  
Energy Gap ◽  
Landau Levels ◽  
Wide Range ◽  
Magneto Optical Effect ◽  
The Magnetic Field

Oscillations in the magnetic field dependence of interband Faraday rotation in degenerate samples of InSb and PbTe at low temperatures have been observed for photons having a wide range of energies which are less than that corresponding to the forbidden energy gap. These oscillations are attributed to the imbalance of contributions from right and left circularly polarized modes to the total rotation, caused by the blocking of certain interband absorptions by conduction-band electrons. The perturbing effect of the variation of carrier concentration is used as an experimental variable. The relative strengths of the oscillations have been reasonably well accounted for by analysis of the interband selection rules and transition strengths given by a theory due to Boswarva & Lidiard. The positions of the oscillations, which depend on the population of Landau levels in the conduction band, have a reciprocal magnetic field dependence as for the de Haas-van Alphen effect, and have yielded quantitative determinations of energy-band parameters.

Screening of a Positive Muon by a Semion Gas

1991 ◽  
Vol 05 (10) ◽  
pp. 1579-1588 ◽  
Author(s):  
T. McMullen ◽  
P. Jena ◽  
S. N. Khanna
Keyword(s):  
Magnetic Field ◽  
Minimum Energy ◽  
Electron System ◽  
Electron Systems ◽  
Correlated Electron Systems ◽  
Muon Site ◽  
Correlated Electron ◽  
Highly Correlated ◽  
The Magnetic Field ◽  
Positively Charged

μSR is one of the experimental techniques used to search for manifestations of the broken [Formula: see text] and [Formula: see text] symmetries predicted by some theories of highly correlated electron systems. When [Formula: see text] and [Formula: see text] are broken, the screening of the positively charged muon by the electron system generates a magnetic field in addition to any intrinsic magnetic field that may be present. We estimate the magnetic field that is induced at a muon site when the muon is screened by the fractional statistics gas. The value depends on the distance between the muon and the anyon plane, and a simple theoretical approach to the calculation of the minimum energy muon sites is outlined and some results for Bi 2 Sr 2 CaCu 2 O 8 and YBa 2 Cu 3 O 7 are presented.

scholarly journals Quantum Relativistic Electron Gas Expanding in One Dimension

2017 ◽  
Vol 45 ◽  
pp. 1760045 ◽  
Author(s):  
Hugo Pérez Rojas ◽  
Elizabeth Rodríguez Querts ◽  
Aurora Pérez Martínez
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Vector Boson ◽  
Electron Gas ◽  
Electron System ◽  
One Dimension ◽  
Ferromagnetic Behavior ◽  
Boson Field ◽  
Magnetic Field Axis ◽  
The Magnetic Field

Under the action of field intensities around the Schwinger critical field, a dense electron gas behaves as unidimensional, exerting strong pressure along the applied field. We suggest a model for maintaining the magnetic field self-consistently, by assuming spin parallel pairing leading to a partial bosonization of the electron gas, which is described by a charged vector boson field, able to experience condensation, leading to a ferromagnetic behavior. Our aim is to suggest a possible quantum relativistic self-magnetized jet model. High frequency photons will be deviated also along paths parallel to the external field, leading to a model for a jet. Any addition of matter and/or energy to the electron system, would contribute to increase the kinetic energy along the magnetic field axis, an the jet may extend for long distances.

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