DCMPMS Seminars

Zero-resistance states induced by electromagnetic wave excitation in the high mobility GaAs/AlGaAs 2D electron system

by Prof. Ramesh G. Mani (Department of Physics and Astronomy, Georgia State University, Atlanta, USA)

Wednesday, May 31, 2017 from to (Asia/Kolkata)
at AG66
Description
Vanishing electrical resistance in condensed matter introduced the phenomena of superconductivity. More recently, the discovery of quantum Hall effects (QHE) stemmed from studies of zero-resistance states at low temperatures, T, and high magnetic fields, B, in the 2-Dimensional Electron System (2DES). Quantum Hall effect and superconductivity have shown that observations of vanishing resistance in unusual settings can be a harbinger of new physics. It turns that the GaAs/AlGaAs 2DES can also exhibit vanishing diagonal resistance, without Hall resistance quantization, at low T and low B when the specimen is excited by electromagnetic waves in the microwave and terahertz parts of spectrum, and that these zero-resistance-states occur about B = [4/(4j+1)] Bf with j=1,2,3…, where Bf = 2π f m*/e, m* is the electron mass, e is electron charge, and f is the EM-wave frequency.[2] Here, we report recent developments in the study of such photo-excited phenomena at low temperatures, in the large filling factor limit, in this ultra high mobility 2DES.[1]

1) R. G. Mani et al., Nature 420, 646 (2002).