Experimental Study Of Ge Hut Wire Quantum Dot And Microwave Resonator Hybrid System

With the rapid development of semiconductor industry and sustaining process of micro-and nano-fabrication techniques,advanced sciences have stepped into the microcosmic quantum field.The nano-scale quantum dot(QD)ensures the precise manipulation the tunneling of single carrier.The charge states and spin states of QD are two level systems and can be used as the quantum bit(qubit).Measuring and manipulating the quantum states of qubit have been achieved,and quantum information processing and quantum computation have shown their promising potential of powerful and capacious applications.However,an applied quantum information processing need sensitive measurement and scalability with the qubit simultaneously maintains coherence.The superconducting microwave resonator is regarded as the useful tool for sensitive readout of qubit and as a quantum bus for mediating multiple distant qubits,indicating as a feasible scheme of scalable quantum information processing.In this thesis,we mainly study the Ge hut wire QD,as well as the QD/microwave resonator hybrid structure.Furthermore,we investigate the theoretical mechanism and experimental realization of sensitively probe the QD states using the microwave resonator with exquisite details.The main contents of this thesis are listed below:1.A brief introduction of the background and realizing systems of quantum computation,gate-defined QD of semiconductor systems,various novel semiconductor materials,cavity quantum electrodynamics and circuit quantum electrodynamics,the latest process of the strong coupling the charge/spin states of QD to a microwave resonator;2.We experimentally fabricate the Ge hut wire hole SQD and DQD,and introduce the instruments and techniques related to the micro-and nano-fabrication,and introduce the electrode structure,energy level,and fabrication process of Ge hut wire SQD in detail.We experimentally study the contact properties,Coulomb oscillations diagram and Coulomb diamonds diagram,energy level splitting behavoir under magnetic field,and lande g-factor;3.We design and fabricate the hybrid device in which the Ge hut wire SQD is coupled to a superconducting microwave resonator.The amplitude and phase of the microwave resonator can be used as the sensitive sensors to probe the charge states of the SQD.The frequency shift ?fR and frequency width broadening ?fD can be extracted from the microwave single,and used to interpret the measuring mechanism.On the basis of Equation of Motion theory,we determine the hole-resonator coupling rate and evaluate the spin-resonator coupling rate in the Ge hut wire SQD and microwave resonator hybrid system;4.We investigate the probing the properties of QD using the superconducting microwave resonator.The amplitude and phase can be used to detect the complex admittance of QD.The ?fR and ?fD can be deduced from the amplitude and phase responses.The quantitative models are built between the DC transport signal with amplitude and phase.The amplitude and phase can also applied as the sensitive tools to evaluate the tunneling rate of Ge hut wire hole SQD;5.We design and fabricate the hybrid device in which the Ge hut wire DQD is coupled to a superconducting microwave resonator.The coupling mechanism of DQD-resonator is compared between that in SQD-resonator system.And we employ the different theoretical models to explain the microwave response with hole tunneling between the left dot and right dot,and between the dot and lead;The main innovations of this thesis are:1.Designing and fabricating the SQD and DQD based on Ge hut wire;2.We realize the coupling between the Ge hut wire SQD or DQD with a microwave resonator,and the amplitude and phase responses can be used as the sensitive sensors of charge states of QD;3.The ?fR and ?fD can be obtained by integrating the odd and even parts of amplitude and phase signal,or by deducing from amplitude and phase.The quantitative models are built between the DC transport signal with amplitude and phase responses.The complex admittance and tunneling rate of QD are probed by means of amplitude and phase of the microwave resonator;4.On the basis of compressibility of QD as well as the coupling capacitance between the QD and resonator,we can determine the hole-resonator coupling rate in SQD-resonator system,and further evaluate the spin-resonator coupling rate;5.We compare and explain the different coupling mechanisms between SQD-resonator system and DQD-resonator system.And the hole tunneling between the left dot and right dot as well as between the dot and lead are interpreted by means of different theoretical models;...