SrTiO3(001)衬底上单层FeSe超导薄膜的分子束外延生长  

Molecular beam epitaxy of single unit-cell FeSe superconducting films on SrTiO_3(001)

作　　者：王萌[1,2] 欧云波 李坊森[3,2] 张文号[3,2] 汤辰佳 王立莉[3,2] 薛其坤[3] 马旭村[3,2] 

机构地区：[1]北京邮电大学电子工程学院,北京100876 [2]中国科学院物理研究所,表面物理国家重点实验室,北京100190 [3]清华大学,低维量子物理国家重点实验室,北京100084

出　　处：《物理学报》2014年第2期281-285,共5页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11374336,91121004)资助的课题~~

摘　　要：在以前工作的基础上,进一步研究了SrTiO3(001)(STO)衬底上单层FeSe超导薄膜的分子束外延生长.首先,通过去离子水刻蚀、盐酸溶液腐蚀和纯氧气氛中退火等步骤,获得台阶有序、具有单一TiO2终止的原子级平整表面的STO衬底,这是前提条件.这个过程中酸的选择和退火过程中氧的流量是最为关键的因素.其次,在FeSe薄膜的分子束外延生长中,选择适当的Fe源和Se源束流以及衬底温度是关键因素.如选择适当,生长模式为step-?ow生长,这时得到的FeSe薄膜将是原子级平整的.最后一步为退火,这个过程会增强FeSe薄膜结晶性以及它与SrTiO3衬底间的结合强度.Based on our previous work, we have systematically investigated the molecular beam epitaxy growth of single unit-cell FeSe films on SrTiO3（001） substrates and studied the surface morphology by scanning tunneling microscopy. We found that there are three key steps to obtain large-scale uniform one unit-cell superconducting FeSe films. First, the STO（001） substrates should be treated by HCl etching and thermal annealing under oxygen flux so that a specific TiO2-terminated STO（001） surface with well-defined step-terrace structure could be obtained. Second, the Fe and Se fluxes and substrate temperature have to be controlled delicately. At last, post-growth annealing is also critical, which can remove extra Se adatoms, and more importantly facilitate the necessary electron transfer for superconductivity transition.

关 键 词：SrTiO3(001) 单层FeSe薄膜 高温超导 分子束外延 

分 类 号：TN304.054[电子电信—物理电子学]