Microwave Photoexcited Transport Studies In The Fractional Quantum Hall Regime

2022-06-20 Prof. Ramesh Mani, Dept. of Physics & Astronomy, Georgia StateUniversity, Atlanta

ABSTRACT :

A metallic state with a vanishing activation gap, at a filling factor 8/5 in the untilted specimen with n = 2 × 10^11cm^(−2) , and at filling factor 4/3 at n = 1.2 × 10^11cm^(−2) a t a tilt angle of 66 degrees between the magnetic field and the plane of the specimen, is examined through a microwave photo-excited transport study of the GaAs/AlGaAs 2 dimensional electron system (2DES). The results presented here suggest, remarkably, that at the possible degeneracy point of states with different spin polarization, where the 8/5 or 4/3 FQHE vanish, there occurs a peculiar marginal metallic state that differs qualitatively from a quantum Hall insulating state and the usual quantum Hall metallic state. Such a marginal metallic state occurs most prominently at filling factor of 8/5 , and at filling factor of 4/3 under tilt as mentioned above, between span between filling factors 1 and 2, that also includes the 3/2 state, which appears perceptibly gapped in the first instance.

Event Name

Seminars

Place

S N Bose Hall (HSB 210)

Start Time

11.00 AM

End Time

12.00 PM

External Link

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