title: Experimental evidence for direct insulator-quantum Hall transition in multi-layer graphene.
abstract: We have performed magnetotransport measurements on a multi-layer graphene flake. At the crossing magnetic field Bc, an approximately temperature-independent point in the measured longitudinal resistivity ρxx, which is ascribed to the direct insulator-quantum Hall (I-QH) transition, is observed. By analyzing the amplitudes of the magnetoresistivity oscillations, we are able to measure the quantum mobility μq of our device. It is found that at the direct I-QH transition, μqBc ≈ 0.37 which is considerably smaller than 1. In contrast, at Bc, ρxx is close to the Hall resistivity ρxy, i.e., the classical mobility μBc is ≈ 1. Therefore, our results suggest that different mobilities need to be introduced for the direct I-QH transition observed in multi-layered graphene. Combined with existing experimental results obtained in various material systems, our data obtained on graphene suggest that the direct I-QH transition is a universal effect in 2D.
authors: Department of Physics, National Taiwan University, Taipei 106, Taiwan. n-aoki@faculty.chiba-u.jp.
authors: Chiashain
authors: C
authors: Chuang
authors: Li-Hung
authors: LH
authors: Lin
authors: Nobuyuki
authors: N
authors: Aoki
authors: Takahiro
authors: T
authors: Ouchi
authors: Akram M
authors: AM
authors: Mahjoub
authors: Tak-Pong
authors: TP
authors: Woo
authors: Jonathan P
authors: JP
authors: Bird
authors: Yuichi
authors: Y
authors: Ochiai
authors: Shun-Tsung
authors: ST
authors: Lo
authors: Chi-Te
authors: CT
authors: Liang
references: Science. 2008 Apr 18;320(5874):356-8
references: 18420930
references: Science. 2008 Jun 6;320(5881):1308
references: 18388259
references: Science. 2009 Jan 30;323(5914):610-3
references: 19179524
references: Phys Rev B Condens Matter. 1992 Jul 15;46(4):2223-2238
references: 10003898
references: J Phys Condens Matter. 2012 Aug 1;24(30):305302
references: 22771627
references: Nanotechnology. 2013 Apr 26;24(16):165201
references: 23538916
references: Science. 2004 Oct 22;306(5696):666-9
references: 15499015
references: Nanotechnology. 2011 Aug 19;22(33):335701
references: 21775805
references: Science. 2012 Sep 7;337(6099):1196-9
references: 22955829
references: Phys Rev Lett. 2008 May 23;100(20):206801
references: 18518564
references: Nature. 2009 Nov 12;462(7270):192-5
references: 19829294
references: Phys Rev Lett. 1994 Jan 31;72(5):709-712
references: 10056503
references: Nano Lett. 2009 Aug;9(8):2973-7
references: 19639984
references: J Phys Condens Matter. 2012 Oct 10;24(40):405601
references: 22968955
references: Nanoscale Res Lett. 2011 Sep 12;6:526
references: 21910905
references: Nano Lett. 2008 Mar;8(3):902-7
references: 18284217
references: Phys Rev B Condens Matter. 1989 Jan 15;39(2):1120-1124
references: 9948293
references: Phys Rev Lett. 2008 Mar 28;100(12):125504
references: 18517883
references: Science. 2006 May 26;312(5777):1191-6
references: 16614173
references: Nano Lett. 2008 Oct;8(10):3092-6
references: 18798683
references: Nanoscale Res Lett. 2012 Aug 16;7(1):459
references: 22898058
references: Nature. 2009 Nov 12;462(7270):196-9
references: 19881489
references: Nature. 2005 Nov 10;438(7065):201-4
references: 16281031
references: Nanoscale Res Lett. 2011 Feb 11;6(1):131
references: 21711637
references: Phys Rev Lett. 2000 Apr 3;84(14):3141-4
references: 11019032
references: Nature. 2005 Nov 10;438(7065):197-200
references: 16281030
references: Phys Rev Lett. 1993 Aug 30;71(9):1439-1442
references: 10055540
references: Science. 2008 Jul 18;321(5887):385-8
references: 18635798