La掺杂BaSnO_(3)薄膜的低温电输运性质  

Low-temperature electrical transport properties of La doped BaSnO_(3) films

作　　者：杨健 高矿红 李志青 Yang Jian;Gao Kuang-Hong;Li Zhi-Qing(Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology,School of Science,Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学理学院,天津市低维功能材料物理与制备技术重点实验室,天津300350

出　　处：《物理学报》2023年第22期255-261,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12174282)资助的课题。

摘　　要：利用射频磁控溅射技术在MgO(001)单晶基片上沉积了一系列Ba_(0.94)La_(0.06)SnO_(3)薄膜,并对薄膜的结构和电输运性质进行了系统研究.所有薄膜均表现出简并半导体(金属)导电特性:在T>Tmin的高温区(Tmin为电阻最小值对应的温度),薄膜的电阻率随温度的升高而升高,并且与温度的平方呈线性关系.在T<Tmin的低温区域,薄膜的电阻率随温度降低而上升,并且电阻率随lnT呈线性变化,均匀无序系统中的电子-电子相互作用、弱局域效应以及Kondo效应均不能解释这种现象.经过定量分析,发现电阻率在低温下lnT的依赖关系源于颗粒间电子的库仑相互作用.同时,在Ba_(0.94)La_(0.06)SnO_(3)薄膜中也观察到霍尔系数RH与lnT呈线性关系,并且该线性关系也定量的符合金属颗粒体系中库仑相互作用的理论.薄膜断面高分辨透射电子显微镜结果表明,虽然薄膜整体呈现外延结构,但其中存在诸多条状非晶区域,这使得薄膜整体表现出类似金属颗粒膜的电输运性质.本文的结果为金属颗粒系统中库仑相互作用对电导率和霍尔系数修正理论的正确性提供了有力的支持.A series of Ba_(0.94)La_(0.06)SnO_(3) thin films are deposited on MgO(001)single crystal substrates by RF magnetron sputtering method,and their structure and electrical transport properties are systematically investigated.All films reveal degenerate semiconductor(metal)characteristics in electrical transport properties.In the high-temperature region(T>T_(min),where T_(min)is the temperature at which the resistivity reaches a minimum value),the resistivity of each film increases with temperature,and exhibits a linear relationship with the square of the temperature.In the low-temperature region(T<T_(min)),the resistivity increases with decreasing temperature and varies linearly with lnT.This temperature dependent behavior of resistivity cannot be explained by the general electron-electron interaction or weak localization effects in homogeneous disordered conductors and nor by Kondo effect.After quantitative analysis,it is found that the lnT behavior of resistivity at low temperatures can be explained by the electron-electron Coulomb interaction effect in the presence of granularity.In addition,it is found that the Hall coefficient R_(H) also varies linearly with lnT for the Ba_(0.94)La_(0.06)SnO_(3) film,which also quantitatively accords with the theoretical prediction of the electron-electron Coulomb interaction effects in the granular metals.The results of cross-section high-resolution transmission electron microscope indicate that although the films have epitaxial structures as a whole,there are many strip-shaped amorphous regions in films,which makes the films have electrical transport properties similar to those of metal granular films.Our results provide strong support for the validity of the theory concerning the effects of Coulomb interaction on the conductivity and Hall coefficient in granular metals.

关 键 词：透明导电氧化物 金属颗粒系统 电子-电子相互作用 电输运性质 

分 类 号：TB383.2[一般工业技术—材料科学与工程]