Table Of ContentSpringer Series in Materials Science 315
Silvia Haindl
Iron-Based
Superconducting
Thin Films
Springer Series in Materials Science
Volume 315
Series Editors
Robert Hull, Center for Materials, Devices, and Integrated Systems, Rensselaer
Polytechnic Institute, Troy, NY, USA
Chennupati Jagadish, Research School of Physics and Engineering, Australian
National University, Canberra, ACT, Australia
Yoshiyuki Kawazoe, Center for Computational Materials, Tohoku University,
Sendai, Japan
Jamie Kruzic, School of Mechanical & Manufacturing Engineering,
UNSW Sydney, Sydney, NSW, Australia
Richard M. Osgood, Department of Electrical Engineering, Columbia University,
New York, USA
Jürgen Parisi, Universität Oldenburg, Oldenburg, Germany
Udo W. Pohl, Institute of Solid State Physics, Technical University of Berlin,
Berlin, Germany
Tae-Yeon Seong, Department of Materials Science & Engineering,
Korea University, Seoul, Korea (Republic of)
Shin-ichi Uchida, Electronics and Manufacturing, National Institute of Advanced
Industrial Science and Technology, Tsukuba, Ibaraki, Japan
Zhiming M. Wang, Institute of Fundamental and Frontier Sciences - Electronic,
University of Electronic Science and Technology of China, Chengdu, China
TheSpringerSeriesinMaterialsSciencecoversthecompletespectrumofmaterials
research and technology, including fundamental principles, physical properties,
materials theory and design. Recognizing the increasing importance of materials
science in future device technologies, the book titles in this series reflect the
state-of-the-art in understanding and controlling the structure and properties of all
important classes of materials.
More information about this series at http://www.springer.com/series/856
Silvia Haindl
Iron-Based Superconducting
Thin Films
123
Silvia Haindl
WRHI Tokyo Tech
Institute of Innovative Research
Tokyo Institute of Technology
Yokohama,Kanagawa, Japan
ISSN 0933-033X ISSN 2196-2812 (electronic)
SpringerSeries inMaterials Science
ISBN978-3-030-75130-2 ISBN978-3-030-75132-6 (eBook)
https://doi.org/10.1007/978-3-030-75132-6
©SpringerNatureSwitzerlandAG2021
Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart
of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations,
recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission
orinformationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar
methodologynowknownorhereafterdeveloped.
The use of general descriptive names, registered names, trademarks, service marks, etc. in this
publicationdoesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfrom
therelevantprotectivelawsandregulationsandthereforefreeforgeneraluse.
The publisher, the authors and the editors are safe to assume that the advice and information in this
book are believed to be true and accurate at the date of publication. Neither the publisher nor the
authors or the editors give a warranty, expressed or implied, with respect to the material contained
hereinorforanyerrorsoromissionsthatmayhavebeenmade.Thepublisherremainsneutralwithregard
tojurisdictionalclaimsinpublishedmapsandinstitutionalaffiliations.
ThisSpringerimprintispublishedbytheregisteredcompanySpringerNatureSwitzerlandAG
Theregisteredcompanyaddressis:Gewerbestrasse11,6330Cham,Switzerland
Dedicated to kb
Preface
The semimetallic Fe-pnictides and Fe-chalcogenides, which are also known as
‘Fe-based superconductors’, constitute a new class of unconventional supercon-
ductors with maximum critical temperatures ranging 55–60 K (and up to 75 K in
1uc FeSe/SrTiO ).Theirappearanceduring2008andthefollowingyearshascaused
3
anintenseexcitementincondensedmatterphysics.Sincethen,wehavewitnesseda
dynamic development in material synthesis, material analysis and theoretical
description.
Thepurposeofthismonographistoprovideanupdatedoverviewofthevarious
activities and results in thin film research of Fe-based superconductors. The pro-
gress in the growth and study of Fe-based superconducting thin films manifested
itself in the first superconducting LaO1(cid:1)xFxFeAs films prepared by a two-stage
process, the successful application of pulsed laser deposition in the growth of Ba
(Fe1(cid:1)xCox)2As2 and FeSe1(cid:1)xTex films, the establishment of different film growth
techniques in the synthesis of the Fe-oxyarsenides LnO1(cid:1)xFxFeAs (Ln = La, Nd,
Sm), various other Fe-pnictides and Fe-chalcogenides, and, notably, the growth of
FeSe monolayers as well as FeSe/Bi Se heterointerfaces by molecular beam epi-
2 3
taxy. Not only most recent contributions in the engineering of ultrathin films and
heterointerfaces but also ongoing efforts in improving thin film properties for
applications demonstrate that we enter a lively field that is still full of surprises!
Thismonographwasoriginallyplannedasafollow-upprojectafterfinishingthe
first comparative review on Fe-based superconducting thin films in 2014 [1]. Its
intention is not only to provide a thematic introduction for graduate students but
alsotoofferastructuredandcommenteddatacollectionforthinfilmengineersand
scientists working in the field. Readers will be able to quickly identify the state of
knowledge and its relevant resources for Fe-based superconducting thin films with
respect to growth techniques or investigated properties. This monograph also
includes several topics, which are typically omitted in the past published surveys.
Having a great interest in interfaces, ideas for an interface atlas came up, in which
the experimentally available data on different film/substrate combinations are ref-
erenced systematically. It became quickly clear that such a compilation goes
beyond the content that is usually found in review articles. Attention is drawn to
vii
viii Preface
several perspectives with more clarity, such as the difference between
Fe-chalcogenidesasvanderWaals materials andFe-pnictidesaspolarcompounds
and the importance of the control of the film/substrate interface.
The monograph is organized into six chapters. After an introduction to the
materials and physics of Fe-based superconductors (Chap. 1), there are two main
chapters: Thin film growth of Fe-based superconductors (Chap. 2) contains tech-
nicaldetailsofthinfilmengineering,systematicallysortedbygrowthmethodsand
compounds.Mostresourcescoverthedominantlyappliedtechniquesinthegrowth
of Fe-based superconductors: pulsed laser deposition and molecular beam epitaxy.
However, this monograph describes also many other and less applied engineering
routes applied to Fe-pnictide and Fe-chalcogenide films. Thin film studies under
focus (Chap. 6) summarizes various contributions of thin film studies under a
specific topic, including vortex physics, superconductor-to-insulator transitions,
electronic phase diagrams, metastable compounds, FeSe monolayers, Fe-based
superconducting thin films in high magnetic fields, electromagnetic and spectro-
scopic thin film studies and finally irradiation experiments. Three additional
chapters are devoted to the analytical characterization of Fe-pnictide and
Fe-chalcogenide thin films, the analysis of their surfaces (Chap. 3), the
film/substrateinterfaceanalyzedbytransmissionelectronmicroscopy(Chap.4)and
thegrowthandanalysisofmultilayersandheterostructures(Chap.5).Accordingto
the large and growing amount of literature resources, the overview cannot be
complete but offers the main trends in thin film engineering of Fe-based super-
conductors and the most relevant literature.
Finally,IamdeeplygratefultoSaraKateHeukerott,EditoratSpringer,whohas
provided initial support, as well as to all other members of the editorial office.
AlthoughnofundingforthismonographwasprovidedbyWRHITokyoInstituteof
TechnologyaswellastheGermanResearchFoundation(DFG),Iwanttomention
thattheirsupportmadeacontinuousworkonthetopicofFe-basedsuperconducting
thin films possible. Agustín Conde-Gallardo, Carlo Ferdeghini and Makoto
Takahashi are gratefully acknowledged for providing images, which demonstrate
film growth synthesis in their labs, Takahiko Kawaguchi and Hiroshi Ikuta are
gratefully mentioned as previous project partners within one of my DFG projects.
Ialso wouldlike tothank severalpreviouscolleagues andco-authors, inparticular
Erik Kampert and the supportive team at High Magnetic Field Laboratory at
Dresden-Rossendorf (HLD-HZDR: member of the European Magnetic Field
Laboratory), Martin Kidszun, Fritz Kurth, Sebastian Molatta, Andreas Reisner,
Tom Thersleff and Elke Reich as well as Rudolph Hübener, Dieter Kölle and
Reinhold Kleiner for their encouragement and fruitful discussions over the past
years.Lastbutnottheleast,IwanttothankYoshinoriMurabaandJoonhoBangfor
their help with translations of Japanese and Korean sources and Sergey Nikolaev
and Tianping Ying for fruitful discussions.
Tübingen, Germany/Tokyo, Japan Silvia Haindl
Preface ix
Reference
[1] Haindl, S., Kidszun, M., Oswald, S., Hess, C., Büchner, B., et al.: Thin film growth of
Fe-based superconductors: from fundamental properties to functional devices.
Acomparativereview.Rep.Prog.Phys.77,046502(2014)
Contents
1 Introduction to Fe-Based Superconductors. . . . . . . . . . . . . . . . . . . . 1
1.1 Discoveries and the ‘Iron Age’ in Superconductivity. . . . . . . . . . 1
1.2 Compounds and Crystal Structures . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Iron (Fe) and Superconductivity . . . . . . . . . . . . . . . . . . . . . . . . 9
1.4 Electronic Bands and Fermi Surfaces. . . . . . . . . . . . . . . . . . . . . 11
1.5 Nematicity, Magnetism and Superconductivity . . . . . . . . . . . . . . 13
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2 Thin Film Growth of Fe-Based Superconductors . . . . . . . . . . . . . . . 27
2.1 Pulsed Laser Deposition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.1.2 PLD of Fe-Chalcogenides. . . . . . . . . . . . . . . . . . . . . . . . 34
2.1.3 PLD of Fe-Pnictide Compounds with ThCr Si
2 2
Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
2.1.4 PLD of Fe-Oxyarsenides with ZrCuSiAs Structure. . . . . . 60
2.2 Molecular Beam Epitaxy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
2.2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
2.2.2 MBE-Growth of Fe-Chalcogenide Thin Films . . . . . . . . . 69
2.2.3 Fabrication of Fe-Chalcogenide Monolayers . . . . . . . . . . 72
2.2.4 Alkali-Metal Evaporation on Ultrathin FeSe Films. . . . . . 79
2.2.5 Fe-Chalcogenides/Topological Insulators (TIs). . . . . . . . . 80
2.2.6 MBE-Growth of Fe-Pnictides . . . . . . . . . . . . . . . . . . . . . 83
2.3 Other Thin Film Growth Methods . . . . . . . . . . . . . . . . . . . . . . . 93
2.3.1 Two-Stage Synthesis with Postdeposition Annealing . . . . 95
2.3.2 Selenization Methods for FeSe Film Growth . . . . . . . . . . 100
2.3.3 Magnetron Sputtering of Fe-Chalcogenides . . . . . . . . . . . 102
2.3.4 Metal-Organic Chemical Vapor Deposition . . . . . . . . . . . 109
2.3.5 Electrodeposition of FeSe and LiFeAs . . . . . . . . . . . . . . 114
2.3.6 Other Wet Chemical Deposition Processes for FeSe. . . . . 124
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
xi
