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Dr Edward McCann

Dr Edward McCann

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C15 Physics Building
Lancaster University
Bailrigg
Lancaster
United Kingdom
LA1 4YB

+44 (0)1524 593930

Condensed matter theory

Electronic properties of nanostructures

Graphene

Click here for an introductory talk about graphene, given to the general public in Lancaster City centre.

Click here for another introductory talk about graphene, given to the local branch of the Institute of Physics.

My research lies in the area of theoretical condensed matter physics. I'm particularly interested in the electronic properties of nanostructures and graphene. In small structures at low temperature, the quantum mechanics of electrons can be very important: they display wave-like properties including interference effects. This topic - the behaviour of electrons in phase coherent structures - is called mesoscopic physics. In the 1980s and 1990s, mesoscopic physics was studied in metals and semiconductors, but, recently, novel mesoscopic phenomena have been discovered in new materials including carbon nanotubes and graphene. The focus of my present research is to understand how electrons behave in graphene and related materials, including bilayer graphene and graphene multilayers.

Research Interests

Bilayer graphene

My major contribution - with colleague Volodya Fal'ko - was to show that low-energy electrons in bilayer graphene are massive chiral fermions. Their properties are unique: a quadratic energy-momentum dispersion with an unusual type of chirality (connection between the direction of pseudospin and momentum). They have a peculiar energy level spectrum in a magnetic field, including a double-degenerate zero-energy Landau level incorporating two different orbital states with the same energy. This means that, taking into account spin and valley degeneracies, the zero-energy Landau level in a bilayer is 8-fold degenerate, as compared to the 4-fold degeneracy of other bilayer states and the 4-fold degeneracy of all Landau levels in a monolayer. This led to a joint publication with the  Manchester experimental mesoscopic physics group, who observed that the sequence of plateaus in the density dependence of the quantum Hall effect conductivity σxy is different from that of Dirac-type quasiparticles in a graphite monolayer and of non-chiral carriers in conventional semiconductor structures. This experiment confirmed the low-energy theory.

We predicted that it is possible to open a band gap in the energy bands of bilayer graphene. Subsequently, I developed a simple model that describes how the charge carrier density and the gap are tuneable with a gate or with doping. This model is useful because it helps experimentalists to understand the effect of gate potentials on the band structure of bilayer graphene devices.

For an introduction to the theory of electrons in monolayer and bilayer graphene, see my tutorial-style paper (suitable for advanced undergraduate, masters or postgraduate students), published as a chapter in Graphene Nanoelectronics: Metrology, Synthesis, Properties and  Applications, pages 237-275 (Springer-Verlag Berlin Heidelberg 2012).

For more information about bilayer graphene in general, I recently co-authored a review paper, published as Rep. Prog. Phys. 76, 056503 (2013).

Weak localisation magnetoresistance in graphene

The chiral nature of electrons in graphene suppresses backscattering and, thus, can be expected to cause weak antilocalisation and a positive weak-field magnetoresistance. However, this can be true only for purely potential scattering, while any violation of the hexagonal symmetry by static disorder in a realistic graphene sheet or by edges in a narrow wire tends to restore conventional negative magnetoresistance. We showed this by evaluating the dependence of the magnetoresistance of graphene on relaxation rates associated with various possible ways of breaking the high original symmetry of the system. The resulting formula has been used widely to analyse experiments. Recently, we modelled the influence of spin-orbit coupling on weak localisation in graphene.

Trilayer graphene and graphene multilayers

With Mikito Koshino of Tohoku University, Sendai, Japan, I have modelled the electronic properties of graphene trilayers and multilayers. Their properties are sensitive to the way in which the graphene layers are stacked and the way in which external gate voltages, for example, break the layer symmetry. Please see my publication list for further details. In 2011, we organised two workshops, in Lancaster and Windermere, to promote UK-Japan scientific collaboration.

Recently, we wrote a paper with experimental colleagues, led by the group of Jeanie Lau at University of California, Riverside, in which the experiments observed dramatically different transport properties in trilayers with different stacking as well as peculiar behaviour in magnetic fields.

Edward McCann's Publications

2014

Dirac edges of fractal magnetic minibands in graphene with hexagonal moire superlattices

Chen, X., Wallbank, J., Patel, A. A., Mucha-Kruczynski, M., McCann, E. & Falko, V. 5/02/2014 In : Physical Review B. 89, 7, 5 p.075401

Research output: Contribution to journalJournal article

2013

The electronic properties of bilayer graphene

McCann, E. & Koshino, M. 19/04/2013 In : Reports on Progress in Physics. 76, 5, 28 p.056503

Research output: Contribution to journalJournal article

Multilayer graphenes with mixed stacking structure: Interplay of Bernal and rhombohedral stacking

Koshino, M. & McCann, E. 22/01/2013 In : Physical Review B. 87, 4, 12 p.045420

Research output: Contribution to journalJournal article

2012

Evidence for spin memory in the electron phase coherence in graphene

Kozikov, A. A., Horsell, D. W., McCann, E. & Falko, V. 23/07/2012 In : Physical Review B. 86, 4, 5 p.045436

Research output: Contribution to journalJournal article

z -> -z Symmetry of Spin-Orbit Coupling and Weak Localization in Graphene

McCann, E. & Falko, V. 20/04/2012 In : Physical review letters. 108, 16, p. - 5 p.166606

Research output: Contribution to journalJournal article

Electronic properties of monolayer and bilayer graphene

McCann, E. 2012 Graphene Nanoelectronics: Metrology, Synthesis, Properties and Applications. Raza, H. (ed.). Berlin Heidelberg: Springer Verlag, p. 237-275 39 p. (NanoScience and Technology).

Research output: Contribution in Book/Report/ProceedingsChapter

2011

Stacking-dependent band gap and quantum transport in trilayer graphene

Bao, W., Jing, L., Velasco Jr, J., Lee, Y., Liu, G., Tran, D., Standley, B., Aykol, M., Cronin, S. B., Smirnov, D., Koshino, M., McCann, E., Bockrath, M. & Lau, C. N. 12/2011 In : Nature Physics. 7, 12, p. 948-952 5 p.

Research output: Contribution to journalJournal article

Manifestation of LO-LA phonons in Raman scattering in graphene

Ferone, R., Wallbank, J. R., Zolyomi, V., McCann, E. & Falko, V. 1/08/2011 In : Solid State Communications. 151, 16, p. 1071-1074 4 p.

Research output: Contribution to journalJournal article

Landau level spectra and the quantum Hall effect of multilayer graphene

Koshino, M. & McCann, E. 27/04/2011 In : Physical Review B. 83, 16, 9 p.165443

Research output: Contribution to journalJournal article

2010

Comment on “Screening in gated bilayer graphene”

Fogler, M. M. & McCann, E. 22/11/2010 In : Physical Review B. 82, 19, 4 p.197401

Research output: Contribution to journalJournal article

Spin-orbit coupling and broken spin degeneracy in multilayer graphene

McCann, E. & Koshino, M. 15/06/2010 In : Physical Review B. 81, 24, 4 p.241409

Research output: Contribution to journalJournal article

Parity and valley degeneracy in multilayer graphene

Koshino, M. & McCann, E. 12/03/2010 In : Physical Review B. 81, 11, 6 p.115315

Research output: Contribution to journalJournal article

Electron-hole asymmetry and energy gaps in bilayer graphene

Mucha-Kruczynski, M., McCann, E. & Falko, V. 4/03/2010 In : Semiconductor Science and Technology. 25, 3, p. - 6 p.033001

Research output: Contribution to journalScientific review

2009

Staying or going? Chirality decides!

McCann, E. 23/11/2009 In : Physics. 2, p. 98

Research output: Contribution to journalJournal article

Trigonal warping and Berry’s phase Npi in ABC-stacked multilayer graphene.

Koshino, M. & McCann, E. 15/10/2009 In : Physical Review B. 80, 16, p. 165409

Research output: Contribution to journalJournal article

On spectral properties of bilayer graphene: the effect of an SiC substrate and infrared magneto-spectroscopy

Mucha Kruczynski, M., Abergel, D. S. L., McCann, E. & Falko, V. 26/08/2009 In : Journal of Physics: Condensed Matter. 21, 34, 5 p.344206

Research output: Contribution to journalJournal article

The influence of interlayer asymmetry on the magnetospectroscopy of bilayer graphene.

Mucha-Kruczynski, M., McCann, E. & Falko, V. 07/2009 In : Solid State Communications. 149, 27-28, p. 1111-1116 6 p.

Research output: Contribution to journalJournal article

Pseudospin valve in bilayer graphene : towards graphene-based pseudospintronics.

San-Jose, P., Prada, E., McCann, E. & Schomerus, H. 18/06/2009 In : Physical Review Letters. 102, 24, p. 247204

Research output: Contribution to journalJournal article

Gate-induced interlayer asymmetry in ABA-stacked trilayer graphene.

Koshino, M. & McCann, E. 15/03/2009 In : Physical Review B. 79, 12, p. 125443

Research output: Contribution to journalJournal article

2008

Tunable graphene system with two decoupled monolayers

Schmidt, H., Luedtke, T., Barthold, P., McCann, E., Falko, V. & Haug, R. J. 27/10/2008 In : Applied Physics Letters. 93, 17, 3 p.172108

Research output: Contribution to journalJournal article

Characterization of graphene through anisotropy of constant-energy maps in angle-resolved photoemission.

Mucha-Kruczyński, M., Tsyplyatyev, O., Grishin, A., McCann, E., Falko, V., Bostwick, A. & Rotenberg, E. 15/05/2008 In : Physical Review B. 77, 19, p. 195403

Research output: Contribution to journalJournal article

2007

Interlayer asymmetry gap in the electronic band structure of bilayer graphene.

McCann, E. 11/2007 In : physica status solidi (b). 244, 11, p. 4112-4117 6 p.

Research output: Contribution to journalJournal article

QHE and far infra-red properties of bilayer graphene in a strong magnetic field.

Abergel, D. S. L., McCann, E. & Falko, V. 09/2007 In : European Physical Journal - Special Topics. 148, 1, p. 105-115 11 p.

Research output: Contribution to journalJournal article

The low energy electronic band structure of bilayer graphene.

McCann, E., Abergel, D. S. L. & Falko, V. 09/2007 In : European Physical Journal - Special Topics. 148, 1, p. 91-103 13 p.

Research output: Contribution to journalJournal article

Weak localization in monolayer and bilayer graphene.

Kechedzhi, K., McCann, E., Falko, V., Suzuura, H., Ando, T. & Altshuler, B. L. 09/2007 In : European Physical Journal - Special Topics. 148, 1, p. 39-54 16 p.

Research output: Contribution to journalJournal article

Electrons in bilayer graphene.

McCann, E., Abergel, D. S. L. & Fal’ko, V. I. 07/2007 In : Solid State Communications. 143, 1-2, p. 110-115 6 p.

Research output: Contribution to journalJournal article

Weak localization in graphene.

Fal’ko, V. I., Kechedzhi, K., McCann, E., Altshuler, B. L., Suzuura, H. & Ando, T. 07/2007 In : Solid State Communications. 143, 1-2, p. 33-38 6 p.

Research output: Contribution to journalJournal article

Influence of trigonal warping on interference effects in bilayer graphene

Kechedzhi, K., Falko, V. I., McCann, E. & Altshuler, B. L. 27/04/2007 In : Physical review letters. 98, 17, 4 p.176806

Research output: Contribution to journalJournal article

2006

Weak localisation magnetoresistance and valley symmetry in graphene.

McCann, E., Kechedzhi, K., Fal’ko, V. I., Suzuura, H., Ando, T. & Altshuler, B. L. 6/10/2006 In : Physical Review Letters. 97, 14, p. 146805

Research output: Contribution to journalJournal article

Asymmetry gap in the electronic band structure of bilayer graphene.

McCann, E. 10/2006 In : Physical Review B. 74, 16, p. 161403

Research output: Contribution to journalJournal article

Landau level degeneracy and quantum Hall effect in a graphite bilayer.

McCann, E. & Fal’ko, V. I. 3/03/2006 In : Physical Review Letters. 96, 8, p. 086805

Research output: Contribution to journalJournal article

Unconventional quantum Hall effect and Berry’s phase 2pi in bilayer graphene.

Novoselov, K. S., McCann, E., Morozov, S. V., Fal’ko, V. I., Katsnelson, M. I., Zeitler, U., Jiang, D., Schedin, F. & Geim, A. K. 03/2006 In : Nature Physics. 2, 3, p. 177-180 4 p.

Research output: Contribution to journalJournal article

2005

Degeneracy breaking and intervalley scattering due to short-ranged impurities in finite single-wall carbon nanotubes.

McCann, E. & Fal’ko, V. I. 15/02/2005 In : Physical Review B. 71, 8, p. 085415

Research output: Contribution to journalJournal article

2004

Symmetry properties of impurities in metallic single-wall carbon nanotubes.

McCann, E. & Falko, V. I. 10/10/2004 In : International Journal of Modern Physics B. 18, 23-24, p. 3195-3212 18 p.

Research output: Contribution to journalJournal article

Symmetry of boundary conditions of the Dirac equation for electrons in carbon nanotubes.

McCann, E. & Fal’ko, V. I. 7/04/2004 In : Journal of Physics: Condensed Matter. 16, 13, p. 2371-2379 9 p.

Research output: Contribution to journalJournal article

A tunnel junction between a ferromagnet and a normal metal: magnon-assisted contribution to thermopower and conductance

McCann, E. & Falko, V. 01/2004 In : Journal of Magnetism and Magnetic Materials. 268, 1-2, p. 123-131 9 p.

Research output: Contribution to journalJournal article

2003

Andreev reflection and subgap transport due to electron-magnon interactions in ferromagnet-superconductor junctions.

Tkachov, G., McCann, E. & Falko, V. 10/11/2003 In : International Journal of Modern Physics B. 17, 28, p. 5001-5005 5 p.

Research output: Contribution to journalJournal article

Magnon-assisted transport and thermopower in ferromagnet-normal-metal tunnel junctions

McCann, E. & Falko, V. 2003 In : Physical Review B: Condensed Matter. 68, 17, p. - 4 p.172404

Research output: Contribution to journalJournal article

2002

Magnetothermopower and magnon-assisted transport in ferromagnetic tunnel junctions

McCann, E. & Falko, V. 4/11/2002 In : Applied Physics Letters. 81, 19, p. 3609-3611 3 p.

Research output: Contribution to journalJournal article

Giant magnetothermopower of magnon-assisted transport in ferromagnetic tunnel junctions

McCann, E. & Falko, V. 1/10/2002 In : Physical Review B. 66, 13, p. - 8 p.134424

Research output: Contribution to journalJournal article

Subgap transport in ferromagnet-superconductor junctions due to magnon-assisted Andreev reflection

Tkachov, G., McCann, E. & Falko, V. 1/01/2002 In : Physical review b. 65, 2, p. - 15 p.024519

Research output: Contribution to journalJournal article

Magnon-assisted Andreev transport across ferromagnet-superconductor junctions

McCann, E., Tkachov, G. & Falko, V. 01/2002 In : Physica E: Low-dimensional Systems and Nanostructures. 12, 1-4, p. 938-941 4 p.

Research output: Contribution to journalJournal article

2001

Magnon-assisted Andreev reflection in a ferromagnet-superconductor junction

McCann, E. & Falko, V. 11/2001 In : Europhysics Letters. 56, 4, p. 583-589 7 p.

Research output: Contribution to journalJournal article

Correlation-function spectroscopy of inelastic lifetime in heavily doped GaAs heterostructures

Konemann, J., Konig, P., Schmidt, T., McCann, E., Falko, V. & Haug, R. J. 15/10/2001 In : Physical Review B. 64, 15, p. - 12 p.155314

Research output: Contribution to journalJournal article

Parametric correlations of local density-of-states fluctuations in disordered pillars, wires and films

McCann, E. & Falko, V. 6/08/2001 In : Journal of Physics: Condensed Matter. 13, 31, p. 6633-6648 16 p.

Research output: Contribution to journalJournal article

Energy dependence of quasi-particle relaxation in a disordered Fermi liquid.

Schmidt, T., König, P., McCann, E., Falko, V. I. & Haug, R. J. 8/01/2001 In : Physical Review Letters. 86, 2, p. 276-279 4 p.

Research output: Contribution to journalJournal article

Local density of states probed by single electron tunneling

Konemann, J., Konig, P., Schmidt, T., McCann, E., Falko, V. & Haug, R. J. 2001 Electronic Correlations: From Meso- to Nano-Physics. Martin, T., Montambaux, G. & ThanhVan, J. T. (eds.). Les Ulis: E D P SCIENCES, p. 283-286 4 p.

Research output: Contribution in Book/Report/ProceedingsConference contribution

Magnon-assisted Andreev reflection in a ferromagnet-superconductor junction

Falko, V., Tkachov, G. & McCann, E. 2001 Electronic Correlations: From Meso- to Nano-Physics. Martin, T., Montambaux, G. & ThanhVan, J. T. (eds.). Les Ulis: E D P SCIENCES, p. 147-152 6 p.

Research output: Contribution in Book/Report/ProceedingsPaper

Measurement of the energy dependence of phase relaxation by single electron tunneling

Konig, P., Konemann, J., Schmidt, T., McCann, E., Falko, V. & Haug, R. J. 2001 Proceedings of the 25th International Conference on the Physics of Semiconductors : Osaka, Japan, September 17-22, 2000 . Miura, N. & Ando, T. (eds.). Berlin: Springer Verlag, p. 1337-1338 2 p.

Research output: Contribution in Book/Report/ProceedingsConference contribution

2000

Weak localization correction to the ferromagnet-superconductor interface resistance

McCann, E., Falko, V., Volkov, A. F. & Lambert, C. J. 2000 In : Physical Review B. 62, 9, p. 6015-6020 6 p.

Research output: Contribution to journalJournal article

Current Students

Research students currently supervised by Edward McCann include: