Thermally activated conductivity in gapped bilayer graphene

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

This is a theoretical study of electron transport in gated bilayer graphene - a novel semiconducting material with a tunable band gap. It is shown that the which-layer pseudospin coherence enhances the subgap conductivity and facilitates the thermally activated transport. The mechanism proposed can also lead to the non-monotonic conductivity vs. temperature dependence at a band gap size of the order of 10 meV. The effect can be observed in gapped bilayer graphene sandwiched in boron nitride where the electron-hole puddles and flexural phonons are strongly suppressed.

Related collections

Most cited references 9

Record: found
Abstract: found
Article: found

Is Open Access

Two-Dimensional Gas of Massless Dirac Fermions in Graphene

A Firsov, I. Grigorieva, S Dubonos … (2005)

Electronic properties of materials are commonly described by quasiparticles that behave as non-relativistic electrons with a finite mass and obey the Schroedinger equation. Here we report a condensed matter system where electron transport is essentially governed by the Dirac equation and charge carriers mimic relativistic particles with zero mass and an effective "speed of light" c* ~10^6m/s. Our studies of graphene - a single atomic layer of carbon - have revealed a variety of unusual phenomena characteristic of two-dimensional (2D) Dirac fermions. In particular, we have observed that a) the integer quantum Hall effect in graphene is anomalous in that it occurs at half-integer filling factors; b) graphene's conductivity never falls below a minimum value corresponding to the conductance quantum e^2/h, even when carrier concentrations tend to zero; c) the cyclotron mass m of massless carriers with energy E in graphene is described by equation E =mc*^2; and d) Shubnikov-de Haas oscillations in graphene exhibit a phase shift of pi due to Berry's phase.

0 comments Cited 3078 times – based on 0 reviews

Preprint

     Review now

Bookmark

Record: found
Abstract: found
Article: found

Is Open Access

Topological Insulators

, (2011)

Topological insulators are electronic materials that have a bulk band gap like an ordinary insulator, but have protected conducting states on their edge or surface. The 2D topological insulator is a quantum spin Hall insulator, which is a close cousin of the integer quantum Hall state. A 3D topological insulator supports novel spin polarized 2D Dirac fermions on its surface. In this Colloquium article we will review the theoretical foundation for these electronic states and describe recent experiments in which their signatures have been observed. We will describe transport experiments on HgCdTe quantum wells that demonstrate the existence of the edge states predicted for the quantum spin Hall insulator. We will then discuss experiments on Bi_{1-x}Sb_x, Bi_2 Se_3, Bi_2 Te_3 and Sb_2 Te_3 that establish these materials as 3D topological insulators and directly probe the topology of their surface states. We will then describe exotic states that can occur at the surface of a 3D topological insulator due to an induced energy gap. A magnetic gap leads to a novel quantum Hall state that gives rise to a topological magnetoelectric effect. A superconducting energy gap leads to a state that supports Majorana fermions, and may provide a new venue for realizing proposals for topological quantum computation. We will close by discussing prospects for observing these exotic states, a well as other potential device applications of topological insulators.

0 comments Cited 2670 times – based on 0 reviews

Preprint

     Review now

Bookmark

Record: found
Abstract: found
Article: found

Is Open Access

Boron nitride substrates for high-quality graphene electronics

P. Kim, C. Dean, J. Hone … (2010)

Graphene devices on standard SiO2 substrates are highly disordered, exhibiting characteristics far inferior to the expected intrinsic properties of graphene[1-12]. While suspending graphene above the substrate yields substantial improvement in device quality[13,14], this geometry imposes severe limitations on device architecture and functionality. Realization of suspended-like sample quality in a substrate supported geometry is essential to the future progress of graphene technology. In this Letter, we report the fabrication and characterization of high quality exfoliated mono- and bilayer graphene (MLG and BLG) devices on single crystal hexagonal boron nitride (h-BN) substrates, by a mechanical transfer process. Variable-temperature magnetotransport measurements demonstrate that graphene devices on h-BN exhibit enhanced mobility, reduced carrier inhomogeneity, and reduced intrinsic doping in comparison with SiO2-supported devices. The ability to assemble crystalline layered materials in a controlled way sets the stage for new advancements in graphene electronics and enables realization of more complex graphene heterostructres.

0 comments Cited 789 times – based on 0 reviews

Preprint

     Review now

Bookmark

All references

Author and article information

Journal

Publication date Created: 17 December 2011

Publication date Updated: 2012-05-25

Article

DOI: 10.1209/0295-5075/98/47007

ArXiV ID: 1112.4077

SO-VID: 30a60491-a26f-4378-a59b-9d2e83440e84

License:

http://arxiv.org/licenses/nonexclusive-distrib/1.0/

History

Custom metadata

Journal reference EPL 98 (2012) 47007

Comments 6 pages, 6 figures, revised, as published in EPL. To be displayed within Graphene Week 2012 Poster Session I

Categories cond-mat.mes-hall cond-mat.mtrl-sci

Data availability:

Thermally activated conductivity in gapped bilayer graphene

Read this article at

Abstract

Related collections

Communication Through Coherence

Most cited references 9

Two-Dimensional Gas of Massless Dirac Fermions in Graphene

Topological Insulators

Boron nitride substrates for high-quality graphene electronics

Author and article information

Journal

Article

History

Custom metadata

Comments

Comment on this article

Similar content 225

Cited by 1

Most referenced authors 296