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We investigated the peculiarities of non-equilibrium charge configurations in the system of two strongly coupled quantum dots (QDs) weakly connected to the reservoirs in the presence of Coulomb correlations. We revealed that total electron…

Mesoscale and Nanoscale Physics · Physics 2014-09-23 V. N. Mantsevich , N. S. Maslova , P. I. Arseyev

A two-dimensional arrangement of quantum dots with finite inter-dot tunnel coupling provides a promising platform for studying complicated spin correlations as well as for constructing large-scale quantum computers. Here, we fabricate a…

Mesoscale and Nanoscale Physics · Physics 2017-10-11 A. Noiri , K. Kawasaki , T. Otsuka , T. Nakajima , J. Yoneda , S. Amaha , M. R. Delbecq , K. Takeda , G. Allison , A. Ludwig , A. D. Wieck , S. Tarucha

We calculate the charge susceptibility and the linear and differential conductances of a double quantum dot coupled to two metallic reservoirs both at equilibrium and when the system is driven away from equilibrium. This work is motivated…

Mesoscale and Nanoscale Physics · Physics 2018-10-16 V. Talbo , M. Lavagna , T. Q. Duong , A. Crépieux

The ground state of frustrated (antiferromagnetic) triangular molecular magnets is characterized by two total-spin $S =1/2$ doublets with opposite chirality. According to a group theory analysis [M. Trif \textit{et al.}, Phys. Rev. Lett.…

Mesoscale and Nanoscale Physics · Physics 2014-07-01 J. F. Nossa , C. M. Canali

We present studies of the Coulomb blockade and Kondo regimes of transport through a quantum dot connected to current leads through spin-polarizing quantum point contacts (QPCs). This structure, arising from the effect of lateral spin-orbit…

Strongly Correlated Electrons · Physics 2010-12-21 Anh T. Ngo , Edson Vernek , Sergio E. Ulloa

The effects of a nearby two-level charge fluctuator on a double-dot two-spin qubit are studied theoretically. Assuming no direct tunneling between the charge fluctuator and the qubit quantum dots, the Coulomb couplings between the qubit…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Guy Ramon , Xuedong Hu

We analyze the charge and spin dynamics in a DC biased double quantum dot driven by crossed DC and AC magnetic fields. In this configuration, spatial delocalization due to inter-dot tunnel competes with intra-dot spin rotations induced by…

Mesoscale and Nanoscale Physics · Physics 2008-04-14 Rafael Sánchez , Carlos López-Monís , Gloria Platero

Non-adiabatic pumping of discrete charges, realized by a dynamical quantum dot in an AlGaAs/GaAs heterostructure, is studied under influence of a perpendicular magnetic field. Application of an oscillating voltage in the GHz-range to one of…

Current fluctuations can provide additional insight into quantum transport in mesoscopic systems. The present work is carried out for the fluctuation properties of transport through a pair of coupled quantum dots which are connected with…

Mesoscale and Nanoscale Physics · Physics 2009-09-02 JunYan Luo , Xin-Qi Li , YiJing Yan

Exchange-coupled singlet-triplet spin qubits in two gate-defined double quantum dots are considered theoretically. Using charge density operators to describe the double-dot orbital states, we calculate the Coulomb couplings between the…

Mesoscale and Nanoscale Physics · Physics 2015-05-28 Guy Ramon

We discuss the effect of quantum interference on transport through a quantum dot system. We introduce an indirect coherent coupling parameter alpha, which provides constructive/destructive interference in the transport current depending on…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Y. Tokura , H. Nakano , T. Kubo

The Coulomb drag phenomenon in a Coulomb-coupled double quantum dot system is revisited with a simple model that highlights the importance of simultaneous tunneling of electrons. Previously, cotunneling effects on the drag current in…

Mesoscale and Nanoscale Physics · Physics 2018-02-16 Jong Soo Lim , Rosa Lopez , David Sanchez

We study spin-resolved noise in Coulomb blockaded double quantum dots coupled to ferromagnetic electrodes. The modulation of the interdot coupling and spin polarization in the electrodes gives rise to an intriguing dynamical spin…

Mesoscale and Nanoscale Physics · Physics 2015-03-19 JunYan Luo , HuJun Jiao , BiTao Xiong , Xiao-Ling He , Changrong Wang

In a mesoscopic system, under zero bias voltage, a finite charge is transferred by quantum adiabatic pumping by adiabatically and periodically changing two or more control parameters. We obtained expressions for the pumped charge for a ring…

Mesoscale and Nanoscale Physics · Physics 2016-09-22 Masahiko Taguchi , Satoshi Nakajima , Toshihiro Kubo , Yasuhiro Tokura

We present a prescription for generating pure spin current or spin selective current, based on adiabatic quantum pumping in a tight-binding model of a one dimensional conductor. A formula for the instantaneous pumped current is derived…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Sungjun Kim , Kunal K. Das , Ari Mizel

We study non-adiabatic charge pumping through single-level quantum dots taking into account Coulomb interactions. We show how a truncated set of equations of motion can be propagated in time by means of an auxiliary-mode expansion. This…

Mesoscale and Nanoscale Physics · Physics 2012-01-12 Alexander Croy , Ulf Saalmann , Alexis R. Hernández , Caio H. Lewenkopf

We investigate the spin dynamics of a quantum dot with a spin-1/2 ground state in the Coulomb blockade regime and in the presence of a magnetic rf field leading to electron spin resonances (ESR). We show that by coupling the dot to leads,…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Hans-Andreas Engel , Daniel Loss

Non-equilibrium spin transport through an interacting quantum dot is analyzed. The coherent spin oscillations in the dot provide a generating source for spin current. In the interacting regime, the Kondo effect is influenced in a…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Ping Zhang , Qi-Kun Xue , X. C. Xie

In double quantum dot singlet-triplet qubits, the exchange interaction is used in both quantum gate operation and the measurement of the state of the qubit. The exchange can be controlled electronically by applying gate voltage pulses. We…

Mesoscale and Nanoscale Physics · Physics 2013-10-21 Tuukka Hiltunen , Juha Ritala , Topi Siro , Ari harju

We show theoretically that a strongly spin-polarized current can be generated in semiconductors by taking advantage of the ferromagnetic phase of a quantum dot array (QDA). A Hubbard model with coupling to leads is used to study the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 David M. -T. Kuo , Y. -C. Chang