Phase-space for the breakdown of the quantum Hall effect in epitaxial graphene

TL;DR

This study maps the phase-space of quantum Hall effect breakdown in epitaxial graphene, revealing high breakdown currents, temperature dependence, and magnetic field effects up to 30T, with implications for quantum resistance standards.

Contribution

It provides the first detailed phase-space analysis of quantum Hall breakdown in epitaxial graphene, highlighting its robustness and unique magnetic field and temperature dependencies.

Findings

Breakdown currents are nearly 100 times higher than in GaAs devices.

The phase boundary follows a (1-(T/T_c)^2) dependence and persists above 45K at 29T.

The critical current scales as B^{3/2} and T_c as B^{1.88}.

Abstract

We report the phase-space defined by the quantum Hall effect breakdown in polymer gated epitaxial graphene on SiC (SiC/G) as a function of temperature, current, carrier density, and magnetic fields up to 30T. At 2K breakdown currents ($I_c$) almost two orders of magnitude greater than in GaAs devices are observed. The phase boundary of the dissipationless state ($\rho_{xx}=0$) shows a (1-$(T/T_c)^2$) dependence and persists up to $T_c>45K$ at 29T. With magnetic field $I_c$ was found to increase $\propto B^{3/2}$ and $T_c \propto B^{1.88}$. As the Fermi energy approaches the Dirac point, the $\nu=2$ quantized Hall plateau appears continuously from fields as low as 1T up to at least 19T due to a strong magnetic field dependence of the carrier density.