Issue |
EPL
Volume 109, Number 2, January 2015
|
|
---|---|---|
Article Number | 28003 | |
Number of page(s) | 6 | |
Section | Interdisciplinary Physics and Related Areas of Science and Technology | |
DOI | https://doi.org/10.1209/0295-5075/109/28003 | |
Published online | 29 January 2015 |
Molecular beam epitaxy growth of superconducting LiFeAs film on SrTiO3(001) substrate
1 State Key Laboratory of Low- Dimensional Quantum Physics, Department of Physics, Tsinghua University Beijing 100084, China
2 Collaborative Innovation Center of Quantum Matter - Beijing 100084, China
3 RIKEN Center for Emergent Matter Science (CEMS) - Wako, Saitama 351-0198, Japan
(a) shji@mail.tsinghua.edu.cn
(b) xc@mail.tsinghua.edu.cn
(c) qkxue@mail.tsinghua.edu.cn
Received: 26 September 2014
Accepted: 7 January 2015
The stoichiometric “111” iron-based superconductor, LiFeAs, has attacted great research interest in recent years. For the first time, we have successfully grown a LiFeAs thin film by molecular beam epitaxy (MBE) on a SrTiO3(001) substrate, and studied the interfacial growth behavior by reflection high-energy electron diffraction (RHEED) and low-temperature scanning tunneling microscope (LT-STM). The effects of substrate temperature and Li/Fe flux ratio were investigated. A uniform LiFeAs film as thin as 3 quintuple layers (QL) is formed. A superconducting gap appears in LiFeAs films thicker than 4 QL at 4.7 K. When the film is thicker than 13 QL, the superconducting gap determined by the distance between the coherence peaks is about 7 meV, close to the value of bulk material. The ex situ transport measurement of a thick LiFeAs film shows a sharp superconducting transition around 16 K. The upper critical field, $H_{c2}(0)=13.0\ \text{T}$ , is estimated from the temperature-dependent magnetoresistance. The precise thickness and quality control of the LiFeAs film paves the road for growing similar ultrathin iron arsenide films.
PACS: 81.15.Hi – Molecular, atomic, ion, and chemical beam epitaxy / 74.70.Xa – Pnictides and chalcogenides / 68.37.Ef – Scanning tunneling microscopy (including chemistry induced with STM)
© EPLA, 2015
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