Quantum Hall Effect at 40 kelvin: Evidence of MacroscopicQuantization in   the Extreme Soft Limit
  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. 
Timir Datta, Michael Bleiweiss, Anca Lungu, Ming Yin and Zafar Iqbal