Regensburg 2004 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 47: Quantendr
ähte und Korrelationseffekte

HL 47.6: Vortrag

Freitag, 12. März 2004, 12:15–12:30, H15

Realization of a new quantum wire structure fabricated by double cleaved-edge overgrowth — •S. F. Roth, M. Grayson, M. Bichler, D. Schuh, and G. Abstreiter — Walter Schottky Institut TUM, 85748 Garching

We demonstrate a new quantum wire structure, in which the potential over the whole length of the channel can be modulated with atomic precision. Theory [1] shows, that if one exact potential barrier can be introduced into the channel, the conductance obeys a power law in temperature. With two barriers, effects associated with the Coulomb blockade can be observed. Even a Mott-insulating state can be achieved by inserting multiple barriers to modulate the potential periodically and tuning the electron density with a gate. The geometry of our double cleave wires is analogous to quantum wires grown by single cleaved-edge overgrowth [2, 3], except that the channel is oriented along the substrate growth direction. Therefore a variation in the substrate potential is directly transferred to the adjacent quantum wire. The first step to realize the more complicated structures mentioned above is to demonstrate a simple quantum wire in this double cleave geometry. Preliminary results show a conductance plateau at a value of about 2e²/h, which indicates the existence of such a quantum wire. We will report on the behavior of this feature with density, temperature and magnetic field.

[1] C. L. Kane, M. P. Fisher, Phys. Rev. B, 46, 15233 (1992)

[2] A. Yacoby, H. L. Stormer, N. S. Wingreen, L. N. Pfeiffer, K. W. Baldwin and K. W. West, Phys. Rev. Lett., 77, 4612 (1996)

[3] M. Rother, Ph.D. thesis, Walter Schottky Institut TUM (1999)