Coulomb Impurity in Graphene
Speaker:
Dmitry Novikov, Yale University
Date & Time:
November 4, 2008 - 1:30pm
Location:
Room 385E Serin Physics Lab | Coulomb Impurity in Graphene Physics and Astronomy |
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| Dmitry Novikov, Yale University 1:30 PM, Room 385E Serin Physics Lab The problem of a Coulomb impurity in graphene connects transport measurements in a solid-state laboratory with relativistic scattering of Dirac electrons. From a practical point, Coulomb scattering is believed to limit mobility in graphene monolayers. I will discuss both the case of a large charge, where the focus is on the nonlinear screening by the graphene electron system [1], and the subcritical impurity scattering [2] relevant for monovalent donors and acceptors. The exact transport cross-section exhibits a pronounced attraction-repulsion asymmetry [3]: Massless carriers are scattered more strongly when they are attracted to an impurity than when they are repelled from it. This peculiarity of the Rutherford scattering, confirmed recently [4] and absent in a conventional parabolic band, may serve as a means to determine separately the densities of donors and acceptors in the vicinity of a graphene monolayer from a transport measurement. [1] M. M. Fogler, D. S. Novikov, and B. I. Shklovskii, Phys. Rev. B 76, 233402 (2007) [2] D. S. Novikov, Phys. Rev. B 76, 245435 (2007) [3] D. S. Novikov, Appl. Phys. Lett. 91, 102102 (2007) [4] J. H. Chen et al, Nature Physics 4, 377 (2008) |