La2-xSrxCuO4双层薄膜制备及载流子调控超导电性研究

项目名称： La2-xSrxCuO4双层薄膜制备及载流子调控超导电性研究

项目编号： No.61274009

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 无线电电子学、电信技术

项目作者： 沈静琴

作者单位： 浙江理工大学

项目金额： 82万元

中文摘要： 近年来，在La2-xSrxCuO4(LSCO)体系中发现，将一层过掺杂的LSCO薄膜沉积到欠掺杂的LSCO薄膜上可以提高欠掺杂LSCO薄膜的超导转变温度（Tc），虽然这一现象的物理机制还不是很清楚，但是引起了人们的极大兴趣。LSCO材料的Tc随着载流子浓度的变化可以在很宽范围内调控，这让我们想到双层膜中载流子扩散可能是引起Tc变化的重要原因。本项目利用脉冲激光沉积技术在SrTiO3衬底上沉积LSCO薄膜，分别研究a)不同组分薄膜之间引起的超导电性的调制规律；b)衬底载流子浓度对薄膜Tc的影响规律；c)LSCO/Nb：SrTiO3构成的P-N结在Tc附近的电学性能；d)过掺杂薄膜和欠掺杂薄膜在电场作用下的电学特性。旨在发现在薄膜成分不发生变化的情况下，环境载流子浓度变化和通过外场调控载流子浓度变化对LSCO薄膜Tc的影响规律和物理机制，并探索载流子浓度调控Tc在构建新型超导器件上的潜在应用。

中文关键词： 超导异质结；载流子调控；庞磁阻；半导体薄膜；脉冲激光

英文摘要： Recently，it was reported that the superconducting transition temperature( Tc) of bilayers comprising underdoped La2-xSrxCuO4(LSCO) films capped by a thin heavily overdoped LSCO layer was found to increase with respect to Tc of the bare underdoped films.The phenomenon attract researchers much interests,even though the physics mechanism is not clear.For LSCO, the Tc can be tuning in a large range just by changing the carrier density, so the enhancement of Tc in LSCO bilayers is possibility related to the changing of carrier density. In this proposal,pulsed laser deposition(PLD) technique will be used to deposit high quality film on SrTiO3 substrate, the following aspects will be studied: a)the effect of topper layer on the bottom layer,b)the effect of carrier density of substrate on Tc of deposited LSCO film,c)electrical properties of LSCO/Nb:SrTiO3 P-N junction,d)under the electrical field, the electrical transport properties of LSCO bilaryers comprising underdoped layer and overdoped layer.The main goal of this proposal is to deeper understand the role of carrier on the enhancement of Tc,and physic mechanism beneath,explore the potential application in novel superconducting device based on external field tuning carrier density.

英文关键词： superconductor heterostructure；carriers tuning；colossal magnetoresistance；semiconductor thin film；pulsed laser diposition