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We investigate hole spin relaxation in the single- and multi-hole regime in a 2x2 germanium quantum dot array. We use radiofrequency (rf) charge sensing and observe Pauli Spin-Blockade (PSB) for every second interdot transition up to the…

Mesoscale and Nanoscale Physics · Physics 2021-01-26 W. I. L. Lawrie , N. W. Hendrickx , F. van Riggelen , M. Russ , L. Petit , A. Sammak , G. Scappucci , M. Veldhorst

Spin relaxation in undoped quasi-spherical CdS quantum dots at zero magnetic fields is investigated using time- and polarization-resolved transient absorption measurements. Unlike in previous studies of these systems, the measured signals…

Mesoscale and Nanoscale Physics · Physics 2007-09-27 P. Nahálková , D. Sprinzl , P. Malý , P. Němec , V. N. Gladilin , J. T. Devreese

Spin-orbit mediated phonon relaxation in a two-dimensional quantum dot is investigated using different confining potentials. Elliptical harmonic oscillator and cylindrical well results are compared to each other in the case of a…

Mesoscale and Nanoscale Physics · Physics 2017-10-25 C. J. Wesslén , E Lindroth

The electrostatic confinement of massless charge carriers is hampered by Klein tunneling. Circumventing this problem in graphene mainly relies on carving out nanostructures or applying electric displacement fields to open a band gap in…

We theoretically analyse the possibility to electrostatically confine electrons in circular quantum dot arrays, impressed on contacted graphene nanoribbons by top gates. Utilising exact numerical techniques, we compute the scattering…

Mesoscale and Nanoscale Physics · Physics 2016-04-21 Holger Fehske , Georg Hager , Andreas Pieper

We consider a square lattice configuration of circular gate-defined quantum dots in an unbiased graphene sheet and calculate the electronic, particularly spectral properties of finite albeit actual sample sized systems by means of a…

Mesoscale and Nanoscale Physics · Physics 2015-06-19 A. Pieper , R. L. Heinisch , G. Wellein , H. Fehske

Using integrated superconducting single photon detectors we probe ultra-slow exciton capture and relaxation dynamics in single self-assembled InGaAs quantum dots embedded in a GaAs ridge waveguide. Time-resolved luminescence measurements…

Mesoscale and Nanoscale Physics · Physics 2014-09-02 G. Reithmaier , F. Flassig , P. Hasch , S. Lichtmannecker , K. Müller , J. Vuckovic , R. Gross , M. Kaniber , J. J. Finley

We review recent studies on spin decoherence of electrons and holes in quasi-two-dimensional quantum dots, as well as electron-spin relaxation in nanowire quantum dots. The spins of confined electrons and holes are considered major…

Mesoscale and Nanoscale Physics · Physics 2009-07-28 Jan Fischer , Mircea Trif , W. A. Coish , Daniel Loss

We calculate electron and nuclear spin relaxation rates in a quantum dot due to the combined action of Nyquist noise and electron-nuclei hyperfine or spin-orbit interactions. The relaxation rate is linear in the resistance of the gate…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Florian Marquardt , Veniamin A. Abalmassov

We study spin-orbit mediated relaxation and dephasing of electron spins in quantum dots. We show that higher order contributions provide a relaxation mechanism that dominates for low magnetic fields and is of geometrical origin. In the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Pablo San-Jose , Gergely Zarand , Alexander Shnirman , Gerd Schön

The singlet-triplet relaxation in nanowire-based quantum dots induced by confined phonons is investigated theoretically. Due to the quasi-one-dimensional nature of the confined phonons, the singlet-triplet relaxation rates exhibit…

Mesoscale and Nanoscale Physics · Physics 2010-11-05 Y. Yin

We report on an unconventional mechanism of electron scattering in graphene in hybrid Bose- Fermi systems. We study energy-dependent electron relaxation time, accounting for the processes of emission and absorption of a Bogoliubov…

Mesoscale and Nanoscale Physics · Physics 2019-03-13 Meng Sun , K. H. A. Villegas , V. M. Kovalev , I. G. Savenko

We study the electron-phonon relaxation in the model of a granular metal film, where the grains are formed by regularly arranged potential barriers of arbitrary transparency. The relaxation rate of Debye acoustic phonons is calculated,…

Mesoscale and Nanoscale Physics · Physics 2023-11-15 Nikolai A. Stepanov , Mikhail A. Skvortsov

We found analytical solution for the time evolution of localized electron density in a system of two coupled single-level quantum dots (QDs) connected with continuous spectrum states in the presence of Coulomb interaction. This solution…

Mesoscale and Nanoscale Physics · Physics 2013-12-30 P. I. Arseev , N. S. Maslova , V. N. Mantsevich

A quantum mechanical model of two interacting electrons in graphene is considered. We concentrate on the case of zero total momentum of the pair. We show that the dynamics of the system is very unusual. Both stationary and time-dependent…

Strongly Correlated Electrons · Physics 2013-09-18 R. N. Lee , A. I. Milstein , I. S. Terekhov

We investigate heavy-hole spin relaxation and decoherence in quantum dots in perpendicular magnetic fields. We show that at low temperatures the spin decoherence time is two times longer than the spin relaxation time. We find that the spin…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Denis V. Bulaev , Daniel Loss

We investigate the spin relaxation induced by acoustic phonons in the presence of spin-orbit interactions in single electron Si/SiGe lateral coupled quantum dots. The relaxation rates are computed numerically in single and double quantum…

Mesoscale and Nanoscale Physics · Physics 2015-03-17 Martin Raith , Peter Stano , Jaroslav Fabian

We analyze charging effects in graphene quantum dots. Using a simple model, we show that, when the Fermi level is far from the neutrality point, charging effects lead to a shift in the electrostatic potential and the dot shows standard…

Mesoscale and Nanoscale Physics · Physics 2008-02-06 B. Wunsch , T. Stauber , F. Guinea

Spin-phonon interactions are one of the mechanisms limiting the lifetime of spin qubits made in semiconductor quantum dots. At variance with other mechanisms such as charge noise, phonons are intrinsic to the device and can hardly be…

Mesoscale and Nanoscale Physics · Physics 2020-08-19 Jing Li , Benjamin Venitucci , Yann-Michel Niquet

Electron spin decoherence caused by elastic spin-phonon processes is investigated comprehensively in a zero-dimensional environment. Specifically, a theoretical treatment is developed for the processes associated with the fluctuations in…

Other Condensed Matter · Physics 2009-11-11 Y. G. Semenov , K. W. Kim
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