Quantum Coherence Lab

Zumbühl Group


Quantum Wires

Transport and tunneling spectroscopy in quantum wires

[1] Editors suggestion: C. P. Scheller, T.-M. Liu, G. Barak, A. Yacoby, L. N. Pfeiffer, K. W. West and D. M. Zumbühl
Possible Evidence for Helical Nuclear Spin Order in GaAs Quantum Wires
Phys. Rev. Lett. 112, 066801 (February 2014), manuscript pdf

[2] C. P. Scheller, B. Braunecker, D. Loss and D. M. Zumbühl
Spontaneous Helical Order of Electron and Nuclear Spins in a Luttinger Liquid
SPS Progress in Physics 44, 23 (September 2014), manuscript pdf


We perform transport and tunnelling spectroscopy experiments on cleaved edge overgrowth quantum wires [3-5]. Those wires are the probably cleanest one-dimensional systems available today and have been demonstrated to exhibit distinct 1D features such as interaction induced charge fractionalization [6], spin-charge separation [7] and ubiquitous power law scaling. Furthermore interaction of the strongly correlated electronic system with nuclear spins of the GaAs host material lead to a spin selective Peierls-transition, manifesting itself in the combined formation of electronic and nuclear helimagnet at low temperature [8,9], investigated in detail here at University Basel [1,2].

Current Research

Currently we are working on momentum matched tunnelling spectroscopy, previously applied to the study of the underlying quantum wire mode structure [10] and spin-charge separation [7]. Here, tunnelling spectroscopy is used to image the evolution of integer quantum hall edge states with unprecedented precision. The technique allows us to unambiguously demonstrate the chiral nature of edge states, investigate the bulk to edge correspondence of the topologically nontrivial quantum hall effect, and study interaction effects that e.g. lead to edge reconstruction physics.

[3] L. N. Pfeiffer et al., J. Cryst. Growth 127, 849 (1993)
[4] W. Wegschneider et al., Solid State Electron. 37, 547 (1994)
[5] A. Yacoby et al., Phys. Rev. Lett. 77, 4612 (1996)
[6] H. Steinberg et al., Nat. Phys. 4, 116 (2008)
[7] O. M. Auslaender et al., Science 308, 88 (2005)
[8] B. Braunecker et al., Phys. Rev. B 80, 165119 (2009)
[9] B. Braunecker et al., Phys. Rev. B 82, 045127 (2010)
[10] O. M. Auslaender et al., Science 295, 825 (2002)