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We demonstrate electrical control of the spin relaxation time T_1 between Zeeman split spin states of a single electron in a lateral quantum dot. We find that relaxation is mediated by the spin-orbit interaction, and by manipulating the…

Mesoscale and Nanoscale Physics · Physics 2010-09-28 S. Amasha , K. MacLean , Iuliana P. Radu , D. M. Zumbuhl , M. A. Kastner , M. P. Hanson , A. C. Gossard

A pair of coupled dots with one electron in each dot can provide improvements in spin coherence, particularly at an electrical bias called the sweet spot, but few measurements have been performed on self-assembled dots in this regime. Here,…

Mesoscale and Nanoscale Physics · Physics 2022-02-17 Kha X. Tran , Allan S. Bracker , Michael K. Yates , Joel Q. Grim , Samuel G. Carter

We show that resonant driving between the spin up and spin down states of an electron spin-qubit in a quantum dot reduces the occupancy of the dot through leakage to an appropriately tuned lead. A nearby charge sensor measuring the…

Mesoscale and Nanoscale Physics · Physics 2025-03-25 Emily Townsend , Joshua Pomeroy , Garnett W. Bryant

We measure and analyze noise-induced energy-fluctuations of spin qubits defined in quantum dots made of isotopically natural silicon. Combining Ramsey, time-correlation of single-shot measurements, and CPMG experiments, we cover the qubit…

The development of spin qubits for quantum technologies requires their protection from the main source of finite-temperature decoherence: atomic vibrations. Here we eliminate one of the main barriers to the progress in this field by…

Mesoscale and Nanoscale Physics · Physics 2020-04-09 Alessandro Lunghi , Stefano Sanvito

We present a theoretical analysis of the nonlinear bias and temperature dependence of current-voltage characteristics of a spin-valve device which is formed by connecting a quantum dot to two ferromagnetic electrodes whose magnetic moments…

Condensed Matter · Physics 2015-06-25 Baigeng Wang , Jian Wang , Hong Guo

We propose and implement a non-destructive measurement that distinguishes between two-electron spin states in a quantum dot. In contrast to earlier experiments with quantum dots, the spins are left behind in the state corresponding to the…

The temperature dependence of electron spin coherence in singly negatively charged (In,Ga)As/GaAs quantum dots is studied by time-resolved Faraday rotation. The decoherence time T2 is constant on a microsecond scale for temperatures below…

Materials Science · Physics 2008-07-14 F. G. G. Hernandez , A. Greilich , F. Brito , M. Wiemann , D. R. Yakovlev , D. Reuter , A. D. Wieck , M. Bayer

We study the nonequilibrium spin transport through a quantum dot containing two spin levels coupled to the magnetic electrodes. A formula for the spin-dependent current is obtained and is applied to discuss the linear conductance and…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Ping Zhang , Qi-Kun Xue , Yu-Peng Wang , X. C. Xie

Using a consistent quantum-mechanical treatment for the electromagnetic radiation, we theoretically investigate the magnetic spin-flip scatterings of a neutral two-level atom trapped in the vicinity of a superconducting body. We derive a…

Quantum Physics · Physics 2007-05-23 Per Kristian Rekdal , Bo-Sture K. Skagerstam , Ulrich Hohenester , Asier Eiguren

Electron spin relaxation induced by phonon-mediated s-d exchange interaction in a II-VI diluted magnetic semiconductor quantum dot is investigated theoretically. The electron-acoustic phonon interaction due to piezoelectric coupling and…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 W. Yang , K. Chang

We discuss advantages and limitations of the spin noise spectroscopy for characterization of interacting quantum dot systems on specific examples of individual singly and doubly charged quantum dot molecules (QDMs). It is shown that all the…

Mesoscale and Nanoscale Physics · Physics 2013-07-29 Dibyendu Roy , Yan Li , Alex Greilich , Yuriy V. Pershin , Avadh Saxena , Nikolai A. Sinitsyn

We report a measurement of the spin-echo decay of a single electron spin confined in a semiconductor quantum dot. When we tip the spin in the transverse plane via a magnetic field burst, it dephases in 37 ns due to the Larmor precession…

Mesoscale and Nanoscale Physics · Physics 2009-08-17 F. H. L. Koppens , K. C. Nowack , L. M. K. Vandersypen

We report electronic control and measurement of an imbalance between spin-up and spin-down electrons in micron-scale open quantum dots. Spin injection and detection was achieved with quantum point contacts tuned to have spin-selective…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 E. J. Koop , B. J. van Wees , D. Reuter , A. D. Wieck , C. H. van der Wal

Magnetic Resonance Force Microscopy can enable nanoscale imaging of spin lifetime. We report temperature dependent measurements of the spin correlation time $\tau_m$ of the statistical fluctuations of the spin polarization---the spin…

Mesoscale and Nanoscale Physics · Physics 2011-12-12 Kin Chung Fong , Micheal R. Herman , Palash Banerjee , Denis V. Pelekhov , Chris Hammel

Circulating orbital currents produced by the spin-orbit interaction for a single electron spin in a quantum dot are explicitly evaluated at zero magnetic field, along with their effect on the total magnetic moment (spin and orbital) of the…

Mesoscale and Nanoscale Physics · Physics 2014-07-24 J. van Bree , A. Yu. Silov , P. M. Koenraad , M. E. Flatté

We report a comprehensive study of stochastic electron spin fluctuations -- spin noise -- in lightly doped ($n$-type) bulk GaAs, which are measured using sensitive optical magnetometry based on off-resonant Faraday rotation. Frequency…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 S. A. Crooker , L. Cheng , D. L. Smith

The gate fidelity and the coherence time of a qubit are important benchmarks for quantum computation. We construct a qubit using a single electron spin in a Si/SiGe quantum dot and control it electrically via an artificial spin-orbit field…

We study the effects of spin-flip scatterings on the time-dependent transport properties through a magnetic quantum dot attached to normal and ferromagnetic leads. The transient spin-dynamics as well as the steady-state tunneling…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Enrico Perfetto , Gianluca Stefanucci , Michele Cini

Coherent electron spin dynamics in 10-nm-wide InGaAs/InAlAs quantum wells is studied from 10 K to room temperature using time-resolved Kerr rotation. The spin lifetime exceeds 1 ns at 10 K and decreases with temperature. By varying the…

Mesoscale and Nanoscale Physics · Physics 2016-11-03 T. Henn , L. Czornomaz , G. Salis