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We present a general formula of the orbital magnetization of disordered systems based on the Keldysh Green's function theory in the gauge-covariant Wigner space. In our approach, the gauge invariance of physical quantities is ensured from…

Strongly Correlated Electrons · Physics 2015-06-03 Guobao Zhu , Shengyuan A. Yang , Cheng Fang , W. M. Liu , Yugui Yao

A dc current can be pumped through an interacting system by periodically varying two independent parameters such as magnetic field and a gate potential. We present a formula for the adiabatic pumping current in general interacting systems,…

Strongly Correlated Electrons · Physics 2015-06-25 Eran Sela , Yuval Oreg

We calculate the charge current in a metallic ferromagnet to first order in the time derivative of the magnetization direction. Irrespective of the microscopic details, the result can be expressed in terms of the conductivities of the…

Mesoscale and Nanoscale Physics · Physics 2008-01-09 R. A. Duine

Using response theory, we calculate the charge-current vortex generated by spin pumping at a point-like contact in a system with Rashba spin-orbit coupling. We discuss the spatial profile of the current density for finite temperature and…

Mesoscale and Nanoscale Physics · Physics 2021-07-01 Junji Fujimoto , Florian Lange , Satoshi Ejima , Tomonori Shirakawa , Holger Fehske , Seiji Yunoki , Sadamichi Maekawa

Spin pumping and spin-transfer torques are two reciprocal phenomena widely studied in ferromagnetic materials. However, pumping from antiferromagnets and its relation to current-induced torques have not been explored. By calculating how…

Mesoscale and Nanoscale Physics · Physics 2014-08-04 Ran Cheng , Jiang Xiao , Qian Niu , Arne Brataas

The time-dependent thermopower is analyzed through an interacting quantum dot coupled to a time-dependent gate voltage and under the influence of an external magnetic field using the Keldysh nonequilibrium Green's function formalism. Formal…

Mesoscale and Nanoscale Physics · Physics 2012-06-12 M. Bagheri Tagani , H. Rahimpour Soleimani

We develop a time-dependent nonequilibrium Green function (NEGF) approach to the problem of spin pumping by precessing magnetization in one of the ferromagnetic layers within F/I/F magnetic tunnel junctions (MTJs) or F/I/N semi-MTJs in the…

Mesoscale and Nanoscale Physics · Physics 2014-12-08 Farzad Mahfouzi , Jaroslav Fabian , Naoto Nagaosa , Branislav K. Nikolic

We demonstrate a spin pump to generate pure spin current of tunable intensity and polarization in the absence of charge current. The pumping functionality is achieved by means of an ac gate voltage that modulates the Rashba constant…

Mesoscale and Nanoscale Physics · Physics 2009-08-06 Chia-Hui Lin , Chi-Shung Tang , Yia-Chung Chang

Spin current and accumulation generated by the electric field in spin Hall insulator (SHI) are investigated theoretically in terms of the Keldysh formalism. In contrast to the quantum Hall system, there are no massless edge modes in…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Masaru Onoda , Naoto Nagaosa

Spin current plays a central role in spintronics. In particular, finding more efficient ways to generate spin current has been an important issue and studied actively. For example, representative methods of spin current generation include…

Mesoscale and Nanoscale Physics · Physics 2017-06-28 Keita Hamamoto , Motohiko Ezawa , Kun Woo Kim , Takahiro Morimoto , Naoto Nagaosa

In ultrathin ferromagnets deposited on metallic substrates, excitation of precessional motion of the spins produces a spin current in the substrate that transports angular momentum out of the film. This phenomenon is referred to as spin…

Mesoscale and Nanoscale Physics · Physics 2011-12-06 F. S. M. Guimarães , A. T. Costa , R. B. Muniz , D. L. Mills

We theoretically study the spin current between two polarized Fermi gases with repulsive interactions near the itinerant ferromagnetic phase transition. We consider a two-terminal model where the left reservoir is fixed to be fully…

Quantum Gases · Physics 2023-10-16 Tingyu Zhang , Daigo Oue , Hiroyuki Tajima , Mamoru Matsuo , Haozhao Liang

The formula derived by Meir and Wingreen [Phys. Rev. Lett. {\bf 68}, 2512 (1992)] for the electron current through a confined, central region containing interactions is generalized to the case of a nonorthogonal basis set. As in the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Kristian S. Thygesen

We investigate parametric pumping of a spin-polarized current through a nearly-closed quantum dot in a perpendicular magnetic field. Pumping is achieved by tuning the tunnel couplings to the left and right lead - thereby operating the…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 M. Blaauboer , C. M. L. Fricot

The radiation reaction for a point-like charge coupled to a massive scalar field is considered. The retarded Green's function associated with the Klein-Gordon wave equation has support not only on the future light cone of the emission point…

Mathematical Physics · Physics 2012-07-23 Yurij Yaremko

Phenomenological approach is developed in the theory of spin-valve type ferromagnetic junctions to describe exchange switching by current flowing perpendicular to interfaces. Forward and backward current switching effects are described and…

Materials Science · Physics 2007-05-23 E. M. Epshtein , Yu. V. Gulyaev , P. E. Zilberman

The time average of the fully nonlinear current through a double quantum dot, subject to an arbitrary combination of ac and dc voltages, is calculated exactly using the Keldysh nonequilibrium Green function technique. When driven on…

Condensed Matter · Physics 2007-05-23 Charles A. Stafford , Ned S. Wingreen

We analyze the charge and spin pumping in an interacting dot within the almost adiabatic limit. By using a non-equilibrium Green's function technique within the time-dependent slave boson approximation, we analyze the pumped current in…

Mesoscale and Nanoscale Physics · Physics 2011-07-06 F. Romeo , R. Citro

The miniaturization of spintronic devices, specifically, nanoscale devices employing spintronics, has attracted intensive attention from a scientific as well as engineering perspective. In this paper, we study non-Markovian effect on spin…

Mesoscale and Nanoscale Physics · Physics 2019-05-16 Kazunari Hashimoto , Gen Tatara , Chikako Uchiyama

We develop a consistent method for calculating non-equilibrium Green's functions for a nano-sized dot coupled to electron reservoirs by tunneling. The leads are generally at different chemical potentials (non-equilibrium), and the dot may…

Strongly Correlated Electrons · Physics 2007-05-23 Jung Hoon Han
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