Research Of Measurement And Control Electronics In Quantum Transport Experiment

Quantum transport is an electron transport process.The transport properties are dominated by quantum mechanical effects,which caused by the coherence of electron wavefunction in the system.Early studies in this field were carried out in semiconductor inversion layers and metallic samples.Many quantum physical phenomena were discovered,such as weak localization,universal conductance fluctuations,quantum Hall effect,and so on.At present,quantum transport is still one of the popular research directions.In recent research,the transport systems are expanded to new materials such as composite heterojunctions and graphene.The research includes the directions of strongly correlated electronic systems,unconventional superconductivity,topological materiality,quantum computing,quantum simulation,nanoelectronic devices,and so on.Nanodevices are the object of quantum transport research.Nanodevices are regulated by external electric field,magnetic field,stress,vibration and other control conditions,which affect the electron transport process.The main research method is to measure the variation curves of the electrical transport properties of the devices with the control conditions and to analyze the physical processes occurring behind them.Therefore,the electrical transport measurement system is important in the experimental platform,which applies techniques of measurement and control electronics.In general,the development direction of measurement and control electronics in quantum transport experiment is to reduce the measurement system noise and improve the measurement efficiency.With the development of quantum transport research,the demand for electrical transport measurements is more diversified.Currently,experimental groups studying quantum transport have developed different types of measurement systems for their own experimental platforms.However,the existing experimental systems often have problems such as experimental flow relying on software control leading to low efficiency and data processing relying on the performance of the host computer.In quantum transport experiments with more channels,more complex experimental processes and larger data processing volumes,such as multi-field modulation experiments with multiple gates and magnetic field parameters,the number of measurements required increases exponentially with the parameters.The improvement of measurement speed is necessary,which means that the synchronization of the modulation parameters will also be increased.In this study,the research of measurement and control electronics with low noise,high accuracy and high efficiency is carried out to meet the needs of quantum transport research.In this study,the electronic measurement and control methods and measurement indexes required in current experiments are analyzed and summarized,and the electronic measurement and control system is designed.Then schematic and PCB designs were carried out to produce the FPGA-based electronics hardware platform.Subsequently,the research of FPGA-based measurement and control electronics method was carried out,and a fast measurement method for multi-field modulation experiments was proposed.The functional logic of board function control,waveform generation,signal acquisition,data processing algorithm,communication interface,etc.was programmed on FPGA.The experimental software is developed based on C and Lab VIEW.According to the functions and indexes in this design,electronic performance tests and three quantum transport experiments are designed and completed using this measurement and control system.The test and experimental results show that the system can complete the experiments and achieve the designed functions.