9929

9159

كارشناسي ارشد

ماده ي چگال

اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك

1393

ده، 97ص.: مصور، نمودار

ص.ع. به فرسي و انگليسي

1396/09/26

كتابنامه

فيزيك

فيزيك

ID9159

The study of time dependent transient electrical transport through a parallel double quantum dot using non equilibrium Green s function formalism Masume Zand m zand@ph iut ac ir Date of Submission 01 07 2015 Department of Physics Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Dr Farhad Fazileh fazileh@cc iut ac ir Abstract Quantum dots are a kind of produced artificial atoms and typically these are small regions of a semiconductor material with a size of order 100 nm A quantum dot is a nano crystal conducting device including of to several thousand electrons Transport through a quantum dot is an example of quantum coherent process at low temperatures Quantum dots are usually made by forming a two dimensional electron gas in the interface region of a semiconductor heterostructure GaAs AlGaAs and adding an electrostatic potential to metal gates to further confine the electrons to a small region dot in the interface plane A quantum dot is sometimes referred to as a zero dimensional system and its the result of restriction electronic motion in all three dimensions and quantum confinement One of the main features of a quantum dot can be explained by coupling it to leads and passing current along the dot Quantum dots put into a larger class of systems termed mesoscopic which are between microscopic systems and macroscopic bulk matter A system is mesoscopic when the electron s phase coherence length is larger than or nearly equal tothe size of the system L Coupling the electron to its environment can affect phase coherence and phase breaking processes make a change in the state of the environment Microscopic theory of quantum transport including interactions can be explained by Non equilibrium Green s function NEGF formalism which combines quantum dynamics with a statistical description of the dissipative interactions The real power of this formalism is presenting a general approach to dscribe quantum transport in the presence of interaction In this thesis we consider a double quantum dot structure in a parallel geometry which is connected to two linear chain metal leads The transient electric current through this construction is studied by non equilibrium Green s function formalism in zero temperature Keywords quantum dot quantum transport Correlation function Coulomb blocade regime non equilibrium Green s functio

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