Observation of linear-polarization-sensitivity in the microwave-radiation-induced magnetoresistance oscillations

In the quasi two-dimensional GaAs/AlGaAs system, we investigate the effect of rotating \textit{in-situ} the electric field of linearly polarized microwaves relative to the current, on the microwave-radiation-induced magneto-resistance oscillations. We find that the frequency and the phase of the photo-excited magneto-resistance oscillations are insensitive to the polarization. On the other hand, the amplitudes of the magnetoresistance oscillations are remarkably responsive to the relative orientation between the microwave antenna and the current-axis in the specimen. The results suggest a striking linear-polarization-sensitivity in the radiation-induced magnetoresistance oscillations.Comment: 4 figures, 5 page

Microwave-induced electron heating in the regime of radiation-induced magnetoresistance oscillations

We examine the influence of microwave photoexcitation on the amplitude of Shubnikov-de Haas (SdH) oscillations in a two dimensional GaAs/AlGaAs electron system in a regime where the cyclotron frequency, $\omega_{c}$, and the microwave angular frequency, $\omega$, satisfy $2 \omega \le \omega_{c} \le 3.5 \omega$. A SdH lineshape analysis indicates that increasing the incident microwave power has a weak effect on the amplitude of the SdH oscillations, in comparison to the influence of modest temperature changes on the dark-specimen SdH effect. The results indicate negligible electron heating under modest microwave photoexcitation, in good agreement with theoretical predictions.Comment: 5 pages, 4 color figure

Quantum magneto-optics of graphite family

The optical conductivity of graphene, bilayer graphene, and graphite in quantizing magnetic fields is studied. Both dynamical conductivities, longitudinal and Hall's, are analytically evaluated. The conductivity peaks are explained in terms of electron transitions. We have shown that trigonal warping can be considered within the perturbation theory for strong magnetic fields larger than 1 T and in the semiclassical approach for weak fields when the Fermi energy is much larger than the cyclotron frequency. The main optical transitions obey the selection rule with \Deltan = 1 for the Landau number n, however the \Deltan = 2 transitions due to the trigonal warping are also possible. The Faraday/Kerr rotation and light transmission/reflection in the quantizing magnetic fields are calculated. Parameters of the Slonczewski-Weiss-McClure model are used in the fit taking into account the previous dHvA measurements and correcting some of them for the case of strong magnetic fields.Comment: 28 pages, 12 figures. arXiv admin note: text overlap with arXiv:1106.340

References

Picture stories lined by ciliated columnar, stratified squamous or rarely gastric epithelium. Most contain a clear jelly like fluid. These cysts are extramural and share the common muscular wall of the oesophagus [2]. The oesophageal duplication cysts are commonly asymptomatic. If gastric mucosa persists it may lead to ulceration, haemorrhage and perforation. An enlarging cyst can cause dysphagia, airway obstruction and repeated lung infections. Radiographically these cysts appear as a mediastinal mass. Barium studies show a filling defect indistinguishable from common tumours such as leiomyoma. At endoscopy there is a bulge with overlying normal mucosa. If the duplication cyst communicates with the oesopagus the barium fills in a blind pouch [3]. Complete surgical excision is the treatment of choice [4]. Excision is done via thoracotomy or by video assisted thoracoscopy. Regular follow up of these patients is essential as impaired propulsive activity of the oesophagus due to damage to oesophageal musculature may result in gastro-oesophageal reflux disease