Transport in bent quantum wells in the quantum Hall regime

• Applicant: Professor Dr. Gerhard Abstreiter, since 3/2007
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2006 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 27930852

The goal of this research is to characterize a new one-dimensional (1D) conducting system that occurs when quantum well samples that are grown with a 90° bend are brought to the quantum Hall regime. The resulting 1D wire at the corner junction consists of the two counter-chiral quantum Hall edge states combined with a native accumulation wire, and has exhibited metallic, insulating, and critical-like phases depending on filling factor. These samples are grown exclusively at the Walter Schottky Institut, and the recent optimization of (110) facet GaAs growth for both n- and p-type structures allows for a large variety of new structures to be prepared. In addition to existing n-type structures, p-type structures, structures with increased mobility, lower density, and a tunnel barrier at the corner junction can be envisioned. With higher density samples, mobility can be improved and higher order fractions of the fractional quantum Hall effect like ¿ = 2/3 can be explored, and gated samples would allow characterization of the conductance as a function of disorder strength. Depending on the orientation of the magnetic field, the same sample can be studied with equal or non-equal filling factors on both facets in both the integer and fractional quantum Hall regime. Theoretical work predicts that equal filling can realize a Luttinger liquid and non-equal filling should create a novel class of conducting 1D system, neither Luttinger or Fermi liquid, introduced theoretically in Ref. [46].

• DFG Programme: Research Grants
• Ehemaliger Antragsteller: Professor Dr. Matthew Grayson, until 3/2007