Divergent resistance at the Dirac point in graphene: Evidence for a transition in a high magnetic field - Condensed Matter > Mesoscale and Nanoscale PhysicsReport as inadecuate




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Abstract: We have investigated the behavior of the resistance of graphene at the $n=0$Landau Level in an intense magnetic field $H$. Employing a low-dissipationtechnique with power $P<$3 fW, we find that, at low temperature $T$, theresistance at the Dirac point $R 0H$ undergoes a 1000-fold increase from$\sim$10 k$\Omega$ to 40 M$\Omega$ within a narrow interval of field. Theabruptness of the increase suggests that a transition to an insulating, orderedstate occurs at the critical field $H c$. Results from 5 samples show that$H c$ depends systematically on the disorder, as measured by the offset gatevoltage $V 0$. Samples with small $V 0$ display a smaller critical field $H c$.Empirically, the steep increase in $R 0$ fits acccurately aKosterlitz-Thouless-type correlation length over 3 decades. The curves of $R 0$vs. $T$ at fixed $H$ approach the thermal-activation form with a gap$\Delta\sim$15 K as $H\to H c^{-}$, consistent with a field-induced insulatingstate.



Author: Joseph G. Checkelsky, Lu Li, N. P. Ong

Source: https://arxiv.org/







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