Ising quantum Hall ferromagnetism in Landau levels |N| ≥ 1 of bilayer graphene

被引:5
作者
Luo, Wenchen [1 ]
Cote, R. [1 ]
Bedard-Vallee, Alexandre [1 ]
机构
[1] Univ Sherbrooke, Dept Phys, Sherbrooke, PQ J1K 2R1, Canada
基金
加拿大自然科学与工程研究理事会;
关键词
SPONTANEOUS INTERLAYER COHERENCE; POLARIZATION; INSTABILITY; NEUTRALITY; SYSTEMS; STATES;
D O I
10.1103/PhysRevB.90.075425
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
A magnetic field applied perpendicularly to the chiral two-dimensional electron gas (C2DEG) in a Bernal-stacked bilayer graphene quantizes the kinetic energy into a discrete set of Landau levels N = 0, +/- 1, +/- 2, .... While Landau level N = 0 is eightfold degenerate, higher Landau levels (vertical bar N vertical bar >= 1) are fourfold degenerate when spin and valley degrees of freedom are counted. In this work, the Hartree-Fock approximation is used to study the phase diagram of the C2DEG at integer fillings (nu) over tilde = 1,2,3 of these higher Landau levels. At these filling factors, the C2DEG is a valley or spin Ising quantum Hall ferromagnet. At odd fillings, the C2DEG is spin polarized and has all its electrons in one valley or the other. There is no intervalley coherence, in contrast with most of the ground states in Landau level N = 0. At even filling (nu) over tilde = 2, the C2DEG is either fully spin polarized with electrons occupying both valleys or spin unpolarized with electrons occupying one of the two valleys. A finite electric field (or bias) applied perpendicularly to the plane of the C2DEG induces a series of first-order phase transitions between these different ground states. The transport gap or its slope is discontinuous at the bias where a transition occurs. Such discontinuity may result in a change in the transport properties of the C2DEG at that bias.
引用
收藏
页数:12
相关论文
共 43 条
  • [1] Properties of graphene: a theoretical perspective
    Abergel, D. S. L.
    Apalkov, V.
    Berashevich, J.
    Ziegler, K.
    Chakraborty, Tapash
    [J]. ADVANCES IN PHYSICS, 2010, 59 (04) : 261 - 482
  • [2] Quantum Hall effects in graphene-based two-dimensional electron systems
    Barlas, Yafis
    Yang, Kun
    MacDonald, A. H.
    [J]. NANOTECHNOLOGY, 2012, 23 (05)
  • [3] Electronic properties of a biased graphene bilayer
    Castro, Eduardo V.
    Novoselov, K. S.
    Morozov, S. V.
    Peres, N. M. R.
    Lopes dos Santos, J. M. B.
    Nilsson, Johan
    Guinea, F.
    Geim, A. K.
    Castro Neto, A. H.
    [J]. JOURNAL OF PHYSICS-CONDENSED MATTER, 2010, 22 (17)
  • [4] The electronic properties of graphene
    Castro Neto, A. H.
    Guinea, F.
    Peres, N. M. R.
    Novoselov, K. S.
    Geim, A. K.
    [J]. REVIEWS OF MODERN PHYSICS, 2009, 81 (01) : 109 - 162
  • [5] COLLECTIVE MODES OF THE 2-DIMENSIONAL WIGNER CRYSTAL IN A STRONG MAGNETIC-FIELD
    COTE, R
    MACDONALD, AH
    [J]. PHYSICAL REVIEW B, 1991, 44 (16): : 8759 - 8773
  • [6] Validity of the two-component model of bilayer and trilayer graphene in a magnetic field
    Cote, R.
    Barrette, Manuel
    [J]. PHYSICAL REVIEW B, 2013, 88 (24)
  • [7] Biased bilayer graphene as a helical quantum Hall ferromagnet
    Cote, R.
    Fouquet, J. P.
    Luo, Wenchen
    [J]. PHYSICAL REVIEW B, 2011, 84 (23):
  • [8] Magnetization instability in a two-dimensional system
    Daneshvar, AJ
    Ford, CJB
    Simmons, MY
    Khaetskii, AV
    Hamilton, AR
    Pepper, M
    Ritchie, DA
    [J]. PHYSICAL REVIEW LETTERS, 1997, 79 (22) : 4449 - 4452
  • [9] DAS SS, 1996, PERSPECTIVES QUANTUM
  • [10] Ezawa ZF, 2000, QUANTUM HALL EFFECTS, pVII