Study On Growth And Transport Properties Of Lead Telluride Nanowires

With the further deepening of the quantum Hall effect,the scientists noticed the boundary current with the special properties of the quantum Hall effect of the non dissipative properties,is likely to break the curse of Moore’s law,namely the loss of the current semiconductor device in small size and heat production problems.In order to solve the problem of heat loss and current,scientists were peculiar effects of microscopic(negatively charged electrons is no energy loss in the process of moving around the nucleus)inspired by the edge of the current can be used to realize quantum Hall effect.However,the realization of the quantum Hall effect requires a very strong external magnetic field,which poses great difficulties for the practical application of the quantum Hall effect.In order to solve this problem,the scientists try to find a new method to realize the quantum Hall effect without external magnetic field.Through the unremitting efforts of scientists,we finally discovered the quantum anomalous Hall effect and the quantum spin Hall effect.The two special effects of quantum Hallr effect can be realized without using external magnetic field.The quantum spin Hall effect can produce edge currents only when the spin orbit coupling is strong enough.The quantum anomalous Hall effect is mainly achieved by using the spontaneous magnetization produced by the material itself to realize the quantum Hall state.The two special quantum effects found for wide application of quantum Hall effect,with a new opportunity,scientists began actively looking for new material to achieve the quantum Hall effect,namely 2D topological insulator.The appearance of topological insulators opened the door of the quantum Hall effect,brings hope for the realization of quantum Hall effect in electronic devices for daily use in high-speed electronic devices so as to make the preparation of low power consumption as possible.Topological insulator is a new state of matters found in recent years,the performance of insulation band structure and protected by time reversal symmetry metal surface state,without the interference of non magnetic magazines and crystal defects,and has broad application prospects in quantum computation,a new principle of spin electronic devices,nano electronic devices,surface catalysis clean energy and etc..In 2012,a topological insulator caused by mirror symmetry was confirmed in theory,known as the "crystalline topological insulator",then tin telluride(SnTe)and lead telluride(PbTe)by theorists predicted topology of crystalline insulator in high symmetry crystal surface such as {001},{110} and {111} with the topological state conduction,and in experiment through the angular resolution of photoelectric spectroscopy confirmed,they found that attracted extensive research interests and opens the door of the experimental study on amorphous insulator topology.Low dimensional nanostructures with large surface area,can effectively reduce the bulk transmission enhancement of surface state effect on the interference effect of surface and therefore,mainly through the angular resolution of photoelectric spectrum test and research Aharonov-Bohm(AB)and Shubnikov-de Haas interference(SdH)method to verify the oscillation of high symmetry surface in the presence of Dirac electrons.Topological crystalline insulators(TCIs)have attracted worldwide interests since their theoretical predication and created exciting opportunities for studying topological quantum physics and for exploring spintronic applications.In this work,we have successfully synthesized PbTe nanowires via chemical vapor deposition method and demonstrated the existence of topological surface states by their 2D weak anti-localization(WAL)effect and Shubnikov-de Haas oscillations(SdH).More importantly,the surface state has contributed～61%of the total conduction,suggesting dominant surface transport in PbTe nanowire at low temperatures.Our work provides an experimental groundwork for research in(TCIs)and is a step forward for the applications of PbTe nanowire in spintronic devices.