Carrier-lifetime enhancement and mass discontinuity inferred from transport in a parabolic quantum well during subband depopulation

Multiband transport in bilayer graphene at high carrier densities

“…Instead of a monotonic decrease of ρ xx with increasing |n H |, it exhibits an abrupt increase by ∼ 10% symmetrically at both electron and hole sides at n * ∼ |n H | = 2.6 × 10 13 cm −2 , a carrier density which is consistent with theoretical expectations for the onset density of the HES [7,8]. A similarly increasing resistivity at the opening of a new subband was previously observed in 2D electron systems formed in wide GaAs quantum wells [1][2][3], where it was attributed to a decreased overall scattering time τ due to the opening of an additional inter-band scattering channel as the new subbands are populated. Such an inter-band scattering mechanism between the LES and the HES is also expected to give rise to a resistivity increase upon filling of the HES in BLG samples, making it a likely candidate for the origin of the observed resistivity increase.…”

“…This was achieved in 2-dimensional electron gases (2DEGs) formed in GaAs quantum wells [1], where the subbands can be continuously populated and depopulated by inducing parallel magnetic fields. In these 2DEGs, an increased overall scattering rate due to interband scattering was observed upon the single-to multiband transition, [2,3], along with changes in the effective Coulomb potential which led to the observation of new filling factors in the fractional quantum Hall effect [4].…”

Magnetoresistance and electronic structure of asymmetricGaAs/Al0.3Ga0.7AsMakarovskii1, Smrčka2, Vašek3 et al. 2000Phys. Rev. B191171View full textAdd to dashboardCite

“…Instead, we use the measured distance between valleys surrounding individual peaks to identify subband densities. 14 For B < B c,1 one type of oscillations, corresponding to the lower density (antibonding) subband, can be detected at small tilt angles while two subbands are clearly visible at higher angles. With in-creasing B the distribution of electrons between the two subbands changes, as shown in Fig.…”

High-order minibands and interband Landau level reconstruction in graphene moiré superlattices

“…When the carrier density is gradually tuned to , the Fermi surface starts to touch the TDP which is also the onset point of the third miniband. An observed increase of sample resistivity can thus be attributed to the abrupt decrease of the DOS as well as the opening of an additional interband scattering channel [17][18][19] .…”