Quantum turnstile operation of single-molecule magnets

Moldoveanu, V.; Dinu, I. V.; Tanatar, B.; Moca, Cătălin Paşcu

doi:10.1088/1367-2630/17/8/083020

Cited by 5 publications

(3 citation statements)

References 47 publications

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“…There have been several studies of magnetic exchange interaction and the possibilities for electrical control of the interaction and spin transport [39][40][41][42][43][44]. Under non-equilibrium conditions, magnetic molecules show signatures of intrinsic anisotropic exchange interactions that can be used to control molecular spin [41,45], something that may lead to read-and-write capabilities with currents in spintronics devices [46][47][48]. Non-equilibrium studies of transport properties have, moreover, suggested that vibrations coupled to the spin degrees of freedom may induce electrical currents that can provide interesting properties for, e.g., mechanical control of single magnetic molecules [49,50].…”

Section: Introductionmentioning

confidence: 99%

Time-dependent spin and transport properties of a single-molecule magnet in a tunnel junction

Hammar

Fransson

2016

Phys. Rev. B

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In single-molecule magnets, the exchange between a localized spin moment and the electronic background provides a suitable laboratory for studies of dynamical aspects of both local spin and transport properties. Here we address the time-evolution of a localized spin moment coupled to an electronic level in a molecular quantum dot embedded in a tunnel junction between metallic leads. The interactions between the localized spin moment and the electronic level generate an effective interaction between the spin moment at different instances in time. Therefore, we show that, despite being a single spin system, there are effective contributions of isotropic Heisenberg, and anisotropic Ising and Dzyaloshinski-Moriya character acting on the spin moment. The interactions can be controlled by gate voltage, voltage bias, the spin polarization in the leads, in addition to external magnetic fields. Signatures of the spin dynamics are found in the transport properties of the tunneling system, and we demonstrate that measurements of the spin current may be used for read-out of the local spin moment orientation.

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Section: Introductionmentioning

confidence: 99%

Time-dependent spin and transport properties of a single-molecule magnet in a tunnel junction

Hammar

Fransson

2016

Phys. Rev. B

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“…Another relevant class of transport phenomena which can be modeled and understood within the GME method is the electron pumping through QDs with tunable-barriers (see e.g., the recent review [ 57 ]). In this context we investigated the transient response of a quantum dot submitted to a sequence of rectangular pulses applied at the contact to the input [ 58 ] and the turnstile protocol for single-molecule magnets [ 59 ].…”

Section: Many-body Effects In the Transient Regimementioning

confidence: 99%

Generalized Master Equation Approach to Time-Dependent Many-Body Transport

Moldoveanu

Manolescu

Guðmundsson

2019

Entropy

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We recall theoretical studies on transient transport through interacting mesoscopic systems. It is shown that a generalized master equation (GME) written and solved in terms of manybody states provides the suitable formal framework to capture both the effects of the Coulomb interaction and electron-photon coupling due to a surrounding single-mode cavity. We outline the derivation of this equation within the Nakajima-Zwanzig formalism and point out technical problems related to its numerical implementation for more realistic systems which can neither be described by non-interacting two-level models nor by a steady-state Markov-Lindblad equation. We first solve the GME for a lattice model and discuss the dynamics of many-body states in a twodimensional nanowire, the dynamical onset of the current-current correlations in electrostatically coupled parallel quantum dots and transient thermoelectric properties. Secondly, we rely on a continuous model to get the Rabi oscillations of the photocurrent through a double-dot etched in a nanowire and embedded in a quantum cavity. A many-body Markovian version of the GME for cavity-coupled systems is also presented.

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“…In the present work we rely on the generalized master equation (GME) method which was previously used to study the turnstile regime of single-molecule magnets 27 and recently extended for hybrid systems such as NEMS or cavity-QD systems 28 . The model Hamiltonian embodies both the electron-electron interaction within the electronic subsystem and the spin degree of freedom.…”

Section: Introductionmentioning

confidence: 99%

Quantum turnstile regime of nanoelectromechanical systems

Dragomir¹,

Moldoveanu²,

Stanciu³

et al. 2020

Phys. Rev. B

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The effects of a turnstile operation on the current-induced vibron dynamics in nanoelectromechanical systems (NEMS) are analyzed in the framework of the generalized master equation. In our simulations each turnstile cycle allows the pumping of up to two interacting electrons across a biased mesoscopic subsystem which is electrostatically coupled to the vibrational mode of a nanoresonator. The time-dependent mean vibron number is very sensitive to the turnstile driving, rapidly increasing/decreasing along the charging/discharging sequences. This sequence of heating and cooling cycles experienced by the nanoresonator is due to specific vibron-assisted sequential tunneling processes along a turnstile period. At the end of each charging/discharging cycle the nanoresonator is described by a linear combination of vibron-dressed states sν associated to an electronic configuration ν. If the turnstile operation leads to complete electronic depletion the nanoresonator returns to its equilibrium position, i.e. its displacement vanishes. It turns out that a suitable bias applied on the NEMS leads to a slow but complete cooling at the end of the turnstile cycle. Our calculations show that the quantum turnstile regime switches the dynamics of the NEMS between vibron-dressed subspaces with different electronic occupation numbers. We predict that the turnstile control of the electron-vibron interaction induces measurable changes on the input and output transient currents.

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Quantum turnstile operation of single-molecule magnets

Cited by 5 publications

References 47 publications

Time-dependent spin and transport properties of a single-molecule magnet in a tunnel junction

Time-dependent spin and transport properties of a single-molecule magnet in a tunnel junction

Generalized Master Equation Approach to Time-Dependent Many-Body Transport

Quantum turnstile regime of nanoelectromechanical systems

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