Photon-Stimulated Transport in a Quantum Point Contact (Brief Review)

Spectral maximum in the terahertz photoconductance of a quantum point contact

“…From the Heisenberg uncertainty relation, it is possible to estimate quasimomentum ∆p acquired by the electron under transfer through QPC and the half-width of the spectral maximum ∆E ∼ (∆p) 2 /2m * , where m * is the electron effective mass. Taking the uncertainty of the coordinate equal to the half-width of the potential barrier at the Fermi level ∆x ≈ 30 nm, we obtain ∆E ≈ 0.5 meV, which agrees by the order of magnitude with the results of the numerical calculations [17].…”

“…1a). The effect was explained by the photon-stimulated transport (PST) of electrons due to the absorption of photons [15,16,17]. However, the observed disappearance of the photoconductance for a higher photon energy hω 0 = 6.74 meV [15], has not received a clear qualitative explanation, although it agrees with the results of the numerical calculations [7,16].…”

“…The authors of [15,16,17] have discovered and studied for the first time the effect of the giant photoconductance of GaAs QPC under irradiation by terahertz radiation with photon energy hω 0 = 2.85 meV, close to the difference between the Fermi energy and the top of the potential barrier hω 0 = U 0 − E F (Fig. 1a).…”

Resonant tunneling through a potential barrier driven by an oscillating field

“…Particularly, it has been demonstrated that the field can crucially modify electronic characteristics of various condensed-matter nanostructures, including semiconductor quantum wells [8][9][10][11][12], quantum rings [13,14], quantum dots [15,16], topological insulators [17][18][19], carbon nanotubes [20], graphene and related two-dimensional materials [21][22][23][24][25][26][27][28], etc. Among a great many of various nanostructures, the nanostructures exploiting the tunneling of electrons through potential barriers -particularly, quantum point contacts (QPCs) -take deserved place [29][30][31][32][33][34][35][36][37][38][39][40][41][42]. Although tunnel nanostructures are one of building blocks of modern nanoelectronics, the high-frequency control of them still wait for detailed analysis.…”

“…which is often used to describe various quantum systems, including QPCs [42,46,47], where u and w are the effective height and width of the barrier, respectively. Substituting Eq.…”