Enhanced Anisotropic Effective g Factors of an Al10.25Ga0.75N/GaN Heterostructure Based Quantum Point Contact

• Gate-defined quantum point contacts (QPCs) were fabricated with Al0.25Ga0.75N/GaN heterostructures grown by metal organic chemical Vapor deposition (MOCVD). In the transport study of the Zeeman effect, greatly enhanced effective g factors (g*).were obtained. The in-plane g* is found to be 5.5 +/- 0.6, 4.8 0.4, and 4.2 0.4 for the first to the third subband, respectively. Similarly, the out-of-plane g* is 8.3 0.6, 6.7 0.7, and 5.1 0.7. Increasing g* with the population of odd-numbered spin-splitted subbands are obtabed at 14 T. This portion of increase is assumed to arise from the exchange interaction in one-dimensional systems. A careful analysis shows that not only the exchange interaction but the spin orbit interaction (SOI) in the strongly confined QPC contribunts to the enhancement and anisotropy of g* in different subbands. An approach to distinguish the respective contributions from the SOI and exchange interaction is therefore proposed.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Nanoteknik -- Nanoteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Nano-technology -- Nano-technology (hsv//eng)

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Keyword

Quantum point contacts (QPCs)

Al0.25Ga0.75N/GaN heterostructures

effective g factor

spin orbit interaction (SO!)

exchange interaction

Publication and Content Type

art (subject category)

ref (subject category)