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Observation of coulomb blockade and ballistic tunneling in graphene single electron transistor

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Science China(Physics,Mechanics & Astronomy) 2012年第1期55卷 7-10页

作者： TAN ZhenBing LIU GuangTong LU Li YANG ChangLi Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China

A square graphene single electron transistor （SET） was defined with two side gates, and its transport was studied at low temperature at T = 2 K. At zero magnetic field, coulomb blockade oscillations were clearly observed near the Dirac point of this device. At high magnetic field, in the quantum Hall regime, we observed ballistic tunneling of the carders through the graphene SET, contrary to the coulomb blockades observed while approaching the vicinity of the Dirac point.

关键词： graphene single electron transistor coulomb blockade tunneling quantum Hall state

Transmission of electron through an Aharonov-Bohm interferometer with a quantum dot in coulomb blockade regime

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Chinese Physics B 2004年第1期13卷 95-99页

作者：孙科伟熊诗杰 StateKeyLaboratoryofSolidStateMicrostructureandDepartmentofPhysics NanjingUniversityNanjing210093China

We calculate conductance of an Aharonov-Bohm (AB) interferometer for which a single-level quantum dot in the coulomb blockade regime is embedded in one of its arms. Using the Schrodinger equations and taking into account the coulomb interaction on the dot, we calculate conductance G as a function of flux φ threaded through the ring and as a function of gate voltage V applied to the dot. It is found that the AB oscillations of G(φ) depend on the particle occupation on the dot, controlled by V. If the system is closed, there is no loss of particles, G(φ) is periodic and G(φ) = G(-φ), satisfying the Onsager relation. In this case G(φ) can reach its maximum value, 2e2/h, at the resonance. When the system is open, one has G(φ) ≠ G(-φ), G(φ) yields a phase shift which depends on the loss rate of electrons in this open system.

关键词： Aharonov-Bohm interferometer quantum dot coulomb blockade

Controlled crossover of electron transport in graphene nanoconstriction:From coulomb blockade to electron interference

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Chinese Physics B 2023年第7期32卷 489-494页

作者：余炜郭潇蔡煜文俞晓天梁文杰 Beijing National Center for Condensed Matter Physics Beijing Key Laboratory for Nanomaterials and NanodevicesInstitute of PhysicsChinese Academy of Sciences(CAS)Beijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China

The ability to control transport behaviors in nanostructure is crucial for usage as a fundamental research platform as well as a practical *** this study,we report a gate-controlled crossover of electron transport behaviors using graphene nanoconstrictions as a *** observed transport properties span from coulomb blockade-dominated single electron transmission to electron-wave interference-dominated quantum *** drastic modulation is achieved by utilizing a single back gate on a graphene nanoconstriction structure,where the size of nanostructure in the constriction and coupling strength of it to the electrodes can be tuned *** results indicate that electrostatic field by gate voltage upon the confined nanostructure defines both the size of the nanoconstriction as well as its interaction to *** gate voltage raises Fermi level to cross the energy profile in the nanoconstriction,resulting in decreased energy barriers which affect the size of nanoconstriction and transmissivity of *** gate-tunable nanoconstriction device can therefore become a potential platform to study quantum critical behaviors and enrich electronic and spintronic devices.

关键词： graphene nanoconstriction coulomb blockade electron interference gate-tunable

Single-electron pumping in a ZnO single-nanobelt quantum dot transistor

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Science China(Physics,Mechanics & Astronomy) 2020年第6期63卷 97-104页

作者： Hassan Ali Jing Tang Kai Peng SiBai Sun Attia Falak FeiLong Song ShiYao Wu ChenJiang Qian Meng Wang XiTian Zhang Muhammad Aftab Rafiq XiuLai Xu Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Laboratory of Quantum Engineering and Quantum Metrology School of Physics and AstronomySun Yat-Sen University(Zhuhai Campus)Zhuhai 519082China National Center for Nanoscience and Technology Chinese Academy of SciencesBeijing 100190China Department of Physics University of the PunjabQuaid-e-Azam CampusLahore 54000Pakistan Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of EducationSchool of Physics and Electronic EngineeringHarbin Normal UniversityHarbin 150025China Department of Physics and Applied Mathematics Pakistan Institute of Engineering and Applied SciencesIslambad 45650Pakistan CAS Center for Excellence in Topological Quantum Computation School of Physical SciencesUniversity of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China

Diluted magnetic semiconductors(DMSs)have traditionally been employed to implement spin-based quantum computing and quantum information ***,their low Curie temperature is a major hurdle in their use in this field,which creates the necessity for wide bandgap DMSs operating at room *** view of this,a single-electron transistor(SET)with a global back-gate was built using a wide bandgap ZnO nanobelt(NB).Clear coulomb oscillations were observed at 4.2 *** periodicity of the coulomb diamonds indicates that the coulomb oscillations arise from single quantum dots of uniform size,whereas quasi-periodic coulomb diamonds correspond to the contribution of multi-dots present in the ZnO *** applying an AC signal to the global back-gate across a coulomb peak with varying frequencies,single-electron pumping was observed;the increase in current was equal to the production of electron charge and *** current accuracy of about 1%for both single-and double-electron pumping was achieved at a high frequency of 25 *** accurate single-electron pumping makes the ZnO NB SET suitable for single-spin injection and detection,which has great potential for applications in quantum information technology.

关键词： ZnO nanobelt coulomb blockade quantum dot transistor single-electron pumping

Detection of Majorana fermions in an Aharonov-Bohm interferometer

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Chinese Physics B 2014年第5期23卷 478-484页

作者：尚恩明潘义明邵陆兵王伯根 National Laboratory of Solid State Microstructures and School of Physics Nanjing University

By using the non-equilibrium Green＇s function technique, we investigate the electronic transport properties in an Aharonov-Bohm interferometer coupling with Majorana fermions. We find a fixed unit conductance peak which is in-dependent of the other factors when the topological superconductor is grounded. Especially, an additional phase appears when the topological superconductor is in the strong coulomb regime, which induces a new conductance resonant peak compared with the structure of replacing the topological superconductor by a quantum dot, and the conductance oscillation with the magnetic flux reveals a 2π phase shift by raising （lowering） a charge on the capacitor.

关键词： Majorana fermion quantum dot Aharonov-Bohm interferometer coulomb blockade

Current-voltage characteristics of an individual helical CdS nanowire rope

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Chinese Physics B 2008年第4期17卷 1389-1393页

作者：龙云泽王文龙白凤莲陈兆甲金爱子顾长志 College of Physics Science Qingdao University Beijing National Laboratory for Molecular Sciences Institute of ChemistryChinese Academy of Sciences Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences

This paper studies the electronic transport in an individual helically twisted CdS nanowire rope, on which platinum microleads are attached by focused-ion beam deposition. The current-voltage （I - V） characteristics are nonlinear from 300 down to 60 K. Some step-like structures in the I - V curves and oscillation peaks in the differential conductance （dI/dV - V） curves have been observed even at room temperature. It proposes that the observed behaviour can be attributed to coulomb-blockade transport in the one-dimensional CdS nanowires with diameters of 6-10 nm.

关键词： nanowires CdS I - V characteristics coulomb blockade

Cotunneling transport in ultra-narrow gold nanowire bundles

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Nano Research 2013年第9期6卷 644-651页

作者： Anais Loubat Walter Escoffier Lise-Marie Lacroix Guillaume Viau Reasmey Tan Julian Carrey Benedicte Warot-Fonrose Bertrand Raquet Laboratoire National des Champs Magnetiques Intenses CNRS-INSA-UJF-UPS UPR3228 143 avenue de Rangueil F-31400 ToulouseFrance Universite de Toulouse INSA UPS LPCNO (Laboratoire de Physique et Chimie des Nano-Objets) F-31077 Toulouse France CNRS UMR5215 LPCNO F-31077 Toulouse France Centre d'Elaboration de Materiaux et d'Etudes Structurales CNRS 29 rue Jeanne Marvig F-31077 Toulouse France

We investigate the charge transport in close-packed ultra-narrow （1.5 nm diameter） gold nanowires stabilized by oleylamine ligands. We give evidence of charging effects in the weakly coupled one-dimensional （1D） nanowires, monitored by the temperature and the bias voltage. At low temperature, in the coulomb blockade regime, the current flow reveals an original cooperative multi-hopping process between 1D-segments of Au-NWs, minimising the charging energy cost. Above the coulomb blockade threshold voltage and at high temperature, the charge transport evolves into a sequential tunneling regime between the nearest- nanowires. Our analysis shows that the effective length of the Au-NWs inside the bundle is similar to the 1D localisation length of the electronic wave function （of the order of 120 nm _＋ 20 nm）, but almost two orders of magnitude larger than the diameter of the nanowire. This result confirms the high structural quality of the Au-NW segments.

关键词： ultra-narrow goldnanowires 1D nano-objects electronic transport variable cotunneling coulomb blockade

Shapiro effect in mesoscopic LC circuit

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Chinese Physics B 2002年第7期11卷 720-724页

作者：嵇英华罗海梅等 DepartmentofPhysics JiangxiNormalUniversityNanchang330027China

In this paper we consider the movement of an electron in the single electron tunnel process through a mesoscopiccapacitor. The results show that, due to the coulomb force, there is a threshold voltage Vt in the mesoscopic LC *** the external voltage is lower than the threshold voltage, the tunnel current value is zero, and the coulomb blockadephenomenon arises. Furthermore, considering that the mesoscopic dimension is comparable to the coherence length inwhich charge carriers retain the phase remembrance, a weak coupling can be produced through the proximity effectof the normal metal electrons of both electrodes of a mesoscopic capacitor. By varying the external voltage, we canobserve the Shapiro current step on the current-voltage characteristic curve of a mesoscopic LC circuit.

关键词： mesoscopic LC circuit coulomb blockade single electron tunnelling effect Shapiro cur- rent step

A Model of a Single Electron Transistor of Metallic Tunneling Junctions and Its Validation

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Journal of Semiconductors 2005年第7期26卷 1323-1327页

作者：张立辉李志刚康晓辉谢常青刘明中国科学院微电子研究所北京100029

Based on the orthodox theory,a model of a single electron transistor （SET） of metallic tunneling junctions is built using the master equation method. Several parameters of the device, such as capacitance, resistance and temperature,are input into the model and thus the I-V curves are attained. These curves are consistent with those from other experiments; therefore, the model is verified. However, there still exists a difference between simulated results and experimental results,mainly comes from the stationary case of the master equation. In other words, precision of simulated results would be increased if the transient case of the master equation is considered. Moreover, the current increases exponentially at higher drain voltages, which is due to the fact that the barrier suppression is caused by the image charge potential.

关键词： single electron transistor orthodox theory coulomb blockade quantum tunnelling