Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Spin and interaction effects in Shubnikov-de Haas oscillations and the quantum Hall effect in GaN/AlGaN heterostructures
AU - Knap, W
AU - Falko, Vladimir
AU - Frayssinet, E
AU - Lorenzini, P
AU - Grandjean, N
AU - Maude, D
AU - Karczewski, G
AU - Brandt, B L
AU - Lusakowski, J
AU - Grzegory, I
AU - Leszczynski, M
AU - Prystawko, P
AU - Skierbiszewski, C
AU - Porowski, S
AU - Hu, X
AU - Simin, G
AU - Khan, M A
AU - Shur, M S
PY - 2004/5/26
Y1 - 2004/5/26
N2 - We present the results of high magnetic field (up to 30 T) and temperature (50 mK-80 K) dependent transport measurements on a 2DEG in GaN/AlGaN heterojunctions. A high mobility (above 60000 cm(2) V-1 s(-1) at 4 K) 2DEG was obtained by MBE growth of dislocation free GaN and AlGaN layers on semi-insulating bulk GaN substrates. A cyclotron gap and spin splitting are observed. Results from two studies are reported: (i) a tilted field experiment determining the 2DEG g*-factor from the angular modulation of the amplitude of SdH oscillations; (ii) quantum Hall effect measurements determining the activation energies for spin and cyclotron energy gaps at even and odd filling factors. The observed 'cyclotron gap' enhancement is attributed to the effect of electron-electron interaction and it is estimated using the model of a 2D-screened Coulomb potential. The analytic result for the enhancement of the,cyclotron gap' yields an addition to the activation energy, epsilon(even)(x) approximate to kappa(h) over bar omega(c), K = 1.06 roota(2)n(e), which is proportional to the magnetic field and resembles the mass renormalization.
AB - We present the results of high magnetic field (up to 30 T) and temperature (50 mK-80 K) dependent transport measurements on a 2DEG in GaN/AlGaN heterojunctions. A high mobility (above 60000 cm(2) V-1 s(-1) at 4 K) 2DEG was obtained by MBE growth of dislocation free GaN and AlGaN layers on semi-insulating bulk GaN substrates. A cyclotron gap and spin splitting are observed. Results from two studies are reported: (i) a tilted field experiment determining the 2DEG g*-factor from the angular modulation of the amplitude of SdH oscillations; (ii) quantum Hall effect measurements determining the activation energies for spin and cyclotron energy gaps at even and odd filling factors. The observed 'cyclotron gap' enhancement is attributed to the effect of electron-electron interaction and it is estimated using the model of a 2D-screened Coulomb potential. The analytic result for the enhancement of the,cyclotron gap' yields an addition to the activation energy, epsilon(even)(x) approximate to kappa(h) over bar omega(c), K = 1.06 roota(2)n(e), which is proportional to the magnetic field and resembles the mass renormalization.
U2 - 10.1088/0953-8984/16/20/013
DO - 10.1088/0953-8984/16/20/013
M3 - Journal article
VL - 16
SP - 3421
EP - 3432
JO - Journal of Physics: Condensed Matter
JF - Journal of Physics: Condensed Matter
SN - 0953-8984
IS - 20
ER -