Local Compressibility Measurements of Correlated States in Suspended Bilayer Graphene

被引：138

作者：

Martin, J. ^{[1
]}

Feldman, B. E. ^{[1
]}

Weitz, R. T. ^{[1
]}

Allen, M. T. ^{[1
]}

Yacoby, A. ^{[1
]}

机构：

[1] Harvard Univ, Dept Phys, Cambridge, MA 02138 USA

来源：

PHYSICAL REVIEW LETTERS | 2010年 / 105卷 / 25期

基金：

美国国家科学基金会;

关键词：

SINGLE-ELECTRON TRANSISTOR; BROKEN-SYMMETRY STATES; BERRYS PHASE;

D O I：

10.1103/PhysRevLett.105.256806

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

Bilayer graphene has attracted considerable interest due to the important role played by many-body effects, particularly at low energies. Here we report local compressibility measurements of a suspended graphene bilayer. We find that the energy gaps at filling factors nu = +/- 4 do not vanish at low fields, but instead merge into an incompressible region near the charge neutrality point at zero electric and magnetic field. These results indicate the existence of a zero-field ordered state and are consistent with the formation of either an anomalous quantum Hall state or a nematic phase with broken rotational symmetry. At higher fields, we measure the intrinsic energy gaps of broken-symmetry states at nu = 0, +/- 1, and +/- 2, and find that they scale linearly with magnetic field, yet another manifestation of the strong Coulomb interactions in bilayer graphene.

引用

页数：4

共 41 条

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