Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 27: CE: Poster Session
TT 27.27: Poster
Mittwoch, 24. März 2010, 14:00–18:00, Poster D1
Quantum phase transition in a two-subband quantum wire — •Tobias Meng1, Mehul Dixit2, Markus Garst1, Julia Meyer3,2, and Achim Rosch1 — 1Universität zu Köln — 2Ohio State University — 3Universite Joseph Fourier Grenoble
We consider a quantum wire with two subbands close to the Lifshitz transition, at which the second band starts to get filled as a function of an external gate voltage. This quantum phase transition is, generically, characterized by pronounced correlations as the electrons in the second subband are strongly interacting: the diverging density of states close to the band bottom leads to unitary two-particle scattering in the low-energy limit. This effectively generates nodes in the many-body wavefunction of electrons with different spin polarization, and, as a result, the electrons in the second band behave effectively as spinless fermions. We argue that, as a consequence, the interaction between the subbands is dominated by non-local contributions similar to the case of spin-polarized electrons [1,2]. We present an analysis of the leading instabilities at small densities of particles in the second band.
[1] J.S. Meyer, K.A. Matveev, and A.I. Larkin, Phys. Rev. Lett. 98, 126404 (2007)
[2] M. Sitte et al., Phys. Rev. Lett. 102, 176404 (2009)