Plasmon assisted resonant tunneling in a double barrier heterostructure

Tunneling throughX-valley-related impurity states in GaAs/AlAs resonant-tunneling diodes

“…Recent progress in multilayered structure growth technology has made it possible to observe, along with main resonant peaks arising from tunneling through the quasibound states of the well and demonstrated by a pioneering study of RTD, 1 numerous novel peculiarities in the tunneling current. New features in the current-voltage characteristics I(V) provide useful information about phonon-2 and plasmon-assisted tunneling 3 and about coherent and inelastic mechanisms of tunneling through quantumwell ͑QW͒ states. 4 The effect of intrinsic bistability has been observed and its origin was established as a charge buildup in the quantum well of the RTD or in the triangular quantum well of the accumulation layer formed in front of the emitter barrier region.…”

Tunneling spectroscopy of hole plasmons in a valence-band quantum well

“…͑1͒ to hole tunneling we define the energy E HL ϭE(LH1)ϪE(HH1) and we assume that there is only a significant population of the HH1 subband. Unlike the electron case 5 where only one plasmon-assisted process was observed, for holes we have two QW subbands ͑HH1 and LH1͒ relatively close in energy. Therefore, when the system is biased such that the energy of holes in the emitter is slightly higher than E(LH1), we have to consider two plasmonassisted processes; ͑i͒ a hole of energy E H tunnels into the LH1 subband, disposing of its extra energy by the emission of an intrasubband heavy-hole plasmon of frequency HH so that E H ϭE(LH1)ϩប HH ; ͑ii͒ a similar process, this time emitting an intersubband plasmon of frequency HH * so E H ϭE(LH1)ϩប HH * and ប HH * ϭ͓ប 2 HH 2ϩ E HL 2 ͔ 1/2 .…”

“…5 The model includes explicitly the coupling between the holes tunneling from the emitter accumulation layer and the plasmon excitations of the degenerate hole gas in the HH1 subband of the quantum well. Note that, although the voltage across the device is well beyond the HH1 resonance, hole relaxation in the well still leads to a high population of this subband.…”

“…3,4 A satellite feature was observed in the current-voltage characteristics I(V) which arose from the excitation of two-dimensional plasmons in the degenerate electron gas of the quantum well. 5 The satellite was observed at bias voltages slightly beyond the condition for resonant tunneling into the first electronic subband of the quantum well. The excitation energy of the plasmon is provided by the excess energy of electrons tunneling into the quantum well from the negatively biased emitter contact.…”

Many-body blockade of resonant tunneling of two-dimensional electrons

“…Such changes have been observed in two specific situations: as a Fermi-edge singularity for the tunneling of twodimensional ͑2D͒ electrons through a strongly localized state of a single impurity 2 and as a plasmon replica in asymmetric resonant tunneling devices ͑RTD's͒ in the regime of change accumulation. 3 In this paper, we show that electron-electron interaction is also responsible for another qualitative feature which can readily be seen in the behavior of conventional RTD's with a two-dimensional electron gas ͑2DEG͒ at the emitter interface. The interaction leads to a clearly noticeable shift of the tunnel resonance to higher biases when a strong magnetic field is applied perpendicular to the 2DEG.…”