Evidence of both fractional and integer quantum hall effects (QHE) in three dimensional bulk replica opal (250nm diameter) structures of non-crystalline carbon are presented. In a remarkably soft quantum limit of ~ 40K temperature and about one tesla of magnetic field clear hall steps, such as n= 2/3, 4/5, 1 and others were observed to be coordinated with the minima of longitudinal magneto-resistance. This behavior is indicative of macroscopic quantum phenomenon associated with electronic condensation into a strongly correlated quantum liquid (QL). For other systems, such as very high mobility, two-dimensional, electron (hole)-gas or (TDEG) these effects typically arise under high magnetic fields (B) and at low temperatures (T), i.e., in the extreme quantum limit (B/T>1). Currently, QHE is applied as calibration benchmark, international resistance standard, and a characterization technique for semiconductor heterostructures. We believe that applications can be widespread if the devices and the operating conditions were more accessible.
@article{arxiv.cond-mat/0503166,
title = {Quantum Hall Effect at 40 kelvin: Evidence of MacroscopicQuantization in the Extreme Soft Limit},
author = {Timir Datta and Michael Bleiweiss and Anca Lungu and Ming Yin and Zafar Iqbal},
journal= {arXiv preprint arXiv:cond-mat/0503166},
year = {2007}
}