Coherent spectroscopy of a strongly driven triple quantum dot molecule

Abstract

Based on a calculation model, we study the interference phenomena of serially coupled V-type and Λ-type triple quantum dots (CTQDs) driven simultaneously by a strong driving field and a weak probe field. Strongly depending on the configuration of the three-level CTQD, the probe absorption spectra, which are shown in the tunneling current, exhibit various quantum coherence properties. In the case where the two pairs of transitions of the CTQD have a small eigenfrequency difference Δω, the double-coupling effect of the driving field results in two Autler—Townes doublets and one weak Mollow triplet in one spectrum. With the value of Δω increasing, only one Autler—Townes splitting remains due to the single-coupling of the field. We also find that the effect of spontaneous emission of phonons may lead to an obvious background current, which can be used to distinguish which transition is driven by the driving field in experiment. The interesting quantum property of a CTQD revealed in our results suggests its potential applications in quantum modulators and quantum logic devices.

Transport through artificial single-molecule magnets: Spin-pair state sequential tunneling and Kondo effects

“…Although the single molecule magnets like Mn 12 have been trapped in a three-terminal transport setup and the electron transport through a single-molecule transistor can be probed, [3,6] the properties of the setup are dependent on the single molecule magnet and can hardly be tuned once it is fabricated. [21] Thus one thinks of the artificial counterparts to molecules, [22][23][24] such as SMM. The successful fabrication of quantum dot (QD) [25][26][27][28][29][30][31][32][33] doped with a single Mn +2 ion has stimulated many studies on the quantum dot with a single magnetic ion.…”

Fano effect of a laterally coupled vertical triple quantum dot system

“…In the past two decades, electron transport through a coupled quantum dot system has received much attention. [1][2][3][4][5][6][7][8][9] Coupled quantum dots enables one to investigate various important transport phenomena, such as quantum interference, [10,11] Kondo effects, [12][13][14] and the Fano effect [15][16][17][18][19][20][21] for its tunable parameters. Much attention has been paid to the Fano effect, [15][16][17][18][19][20][21] which arises from the interference between the resonant process and non-resonant process.…”

Spin-polarized current in double quantum dots

“…And many interesting optical effects have been found in coupled quantum dots. [7,8] The spin degree of freedom of electrons has great potential as a carrier of classical information (spintronics) [9] and quantum information [10,11] (spin quantum bits). Spintronics is a new research area, in which the spin plays an important role in a lot of new physical phenomena.…”