Quantum Hall Effect at 40 kelvin: Evidence of MacroscopicQuantization in the Extreme Soft Limit

TL;DR

This paper reports the observation of quantum Hall effects at unusually high temperatures (~40K) in bulk non-crystalline carbon structures, indicating macroscopic quantum phenomena in a soft quantum limit.

Contribution

It presents evidence of fractional and integer quantum Hall effects in bulk non-crystalline carbon at high temperatures, expanding the understanding of quantum phenomena beyond traditional low-temperature, high-field conditions.

Findings

Quantum Hall effects observed at ~40K in bulk carbon structures.

Hall steps correlated with minima in magneto-resistance.

Indication of macroscopic quantum phenomena in a soft quantum limit.

Abstract

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.