Two-dimensional Electron Systems
Source: Excerpts from the 9th APWMP Poster by C. Villagonzalo and R. Gammag and the
Structure and Dynamics Group 2009 Annual Report
"Two dimensional electron systems (2DES) are interesting because
- they demonstrate macroscopic quantum mechanical effects such as the quantum Hall phenomenon and the de Haas - van Alphen oscillations,
- they serve as the transport layer in semiconductor heterostructures, and
- their discretized energy spectrum (Landau levels) formed under an applied magnetic field and low temperatures are shown by experiments to be broadened indicating the presence of disorder."
"Magnetization and heat capacity experimental measurements have provided indirect pictures on the structure of the 2DES energy spectra. The group's numerical and analytical studies will focus on how temperature- and magnetic field- dependent energy fluctuations in the 2DES spectra and its corresponding density of states will affect its magnetic and thermodynamic properties. "
(Graphics by R. Gammag [2008, Ref. 2])
"It is found that the Landau level broadening due to disorder in a 2DES causes variations in its interlevel and intralevel excitations. A characteristc low temperature has been determined in which the broadening parameter has no effect on the specific heat."
References:
- C. Villagonzalo and R. Gammag, The intrinsic features of the specific heat at half-filled Landau levels of two-dimensional electron systems, Journal of Low Temperature Physics (2010),
doi: 10.1007/s10909-010-0259-3 [preprint] - R. Gammag and C. Villagonzalo, The interplay of Landau level broadening and temperature on two-dimensional electron systems, Solid State Communications (2008) 146, 487 - 490.
doi: 10.1016/j.ssc.2008.03.042 [preprint]
