Searching for the fractional quantum Hall effect in graphite

• Published in: Physical review letters Vol. 103; no. 11; p. 116802
• Main Authors: Kopelevich, Y, Raquet, B, Goiran, M, Escoffier, W, da Silva, R R, Pantoja, J C Medina, Luk'yanchuk, I A, Sinchenko, A, Monceau, P
• Format: Journal Article
• Language: English
• Published: United States 11.09.2009
• ISSN: 0031-9007
• DOI: 10.1103/physrevlett.103.116802

Measurements of basal plane longitudinal rho(b)(B) and Hall rho(H)(B) resistivities were performed on highly oriented pyrolytic graphite samples in a pulsed magnetic field up to B=50 T applied perpendicular to graphene planes, and temperatures 1.5 K<or=T<or=4.2 K. At B>30 T and for all studied samples, we observed a sign change in rho(H)(B) from electron- to holelike. For our best quality sample, the measurements revealed the enhancement in rho(b)(B) for B>34 T (T=1.8 K), presumably associated with the field-driven charge density wave or Wigner crystallization transition. In addition, well-defined plateaus in rho(H)(B) were detected in the ultraquantum limit revealing possible signatures of the fractional quantum Hall effect in graphite.