Real space imaging of the superconducting vortex lattice: Recent - - PowerPoint PPT Presentation

Real space imaging of the superconducting vortex lattice: Recent results and prospects Hermann Suderow

Laboratorio de Bajas Temperaturas Departamento de Física de la Materia Condensada Instituto de Ciencia de Materiales Nicolás Cabrera Center for Condensed Matter Physics (IFIMAC) Universidad Autónoma de Madrid (UAM)

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 1

• Real space imaging and spectroscopy of the vortex lattice
• Superconducting CaKFe4As4, bandstructure, vortex core, vortex lattice

and pinning

• Vortex lattice structure: interactions vs disorder
• Observation of vortex creep on cooling
• Josephson effect at atomic scale

Real space imaging of the superconducting vortex lattice: Recent results and prospects

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 2

Tunneling Piezoelectrics

V A y x 20 ,  

The birth of scanning probe microscopy

1Å ~ 250 mV

The invention of the scanning tunneling microscope Gerd Binnig and Heini Rohrer, Zurich, 1982

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Tunneling

Conduction through constrictions

Imaging superconducting vortex cores and lattices with a STM

• H. Suderow, I. Guillamón, J.G. Rodrigo and S. Vieira
• Superc. Sci. Techn., 27, 063001 (2014)

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0.2 0.4 0.6 0.8 1.0 1.2 1.4 0.0 0.5 1.0 1.5 2.0 2.5 3.0 G/G0 z (nm)

Tunneling

Conduction through constrictions

Imaging superconducting vortex cores and lattices with a STM

• H. Suderow, I. Guillamón, J.G. Rodrigo and S. Vieira
• Superc. Sci. Techn., 27, 063001 (2014)

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 5

d

vacuum

+eV

EF,S EF,T   μ Fp Fm Distance Energy tip sample

 

   

 

 

 

 

         

 * * 2 2

2 ; ; 1 1 ) ( 1 2

 

       

            

dS m M E E e E f E E M eV E f E f e I

T k E E

B F

 

Empty states EF,T Distance Energy tip sample Filled states EF,T Distance Energy tip sample EF,S EF,S

Tunnelling from a Many-Particle Point of View

• J. Bardeen

PRL, 6, 57 (1961)

Tunneling

The tunneling current: Bardeen’s formalism

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Ideal tip, low bias voltage (V=0) :

     

F F

E E E I ,

2

d d   

  

  

d0

STM: Contour map of the local DOS

     

eV E T E dE V I

S eV E E

F F

, , , , r d d 







The tunneling current: Tersoff-Haman

Theory and Application for the Scanning Tunneling Microscope

• J. Tersoff and D. R. Hamann

PRL, 50, 1998 (1983) Rubén Pérez UAM

Tunneling

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The tunneling current: Chen Directional tunneling

Empty states EF,T Distance Energy tip sample Filled states EF,T Distance Energy tip sample EF,S EF,S

     

eV E T E dE V I

S eV E E

F F

, , , , r d d 







Tunneling

Microscopic (Cp, k, , …) Empty + filled states (ARPES, dHvA) Bandstructure (ARPES) Real space (neutrons, x-ray)

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Random Hyperuniform Working in real space Imaging Vortex lattice ?

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

 

i

e 

S=0 L=0

Microscopic theory

• J. Bardeen, L. Cooper, J. Schrieffer (BCS, 1957)

Cooper pairs Kohn, Luttinger (1965)

S=1 L=1



   

' ' ' ' 2 k k k kk k

E V

E k e(k) e(k) kF 

• kF

𝜁 𝑙 2 + Δ2

Superconductor Tunneling

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• 1

1 0.0 0.5 1.0 1.5

MgB2

normalized conductance

Normalized bias voltage

STM Tunneling

Bardeen’s formalism

     

F F

E N E E I , d d

2

  

  

 

dE V eV E f E N dV dI      ) ( ) ( The local density of states

• P. Martínez-Samper et al. Physica C 2003



 

i i 2 i 2 S

(k) Δ E E (E) N 

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10 100 1000 10000 0.1 1 10 100

Critical temperature Tc Fermi temperature TF

• 1.2
• 0.9
• 0.6
• 0.3

0.0 0.3 0.6 0.9 1.2 0.0 0.5 1.0 1.5 2.0 2.5 T = 150 mK 200 G  = 0.28 meV

Normalized conductance Bias voltage (mV)

• 3
• 2
• 1

1 2 3 0.0 0.5 1.0 1.5 2.0 2.5 Normalized conductance Bias voltage (mV)

• 3
• 2
• 1

1 2 3 0.0 0.5 1.0 1.5

Normalized conductance Bias voltage (mV)

• 0.8
• 0.6
• 0.4
• 0.2

0.0 0.2 0.4 0.6 0.8 0.0 0.5 1.0 1.5 2.0

T = 0.1 K

Voltage (mV) Normalized conductance

2H-TaS2

• 1

1 0.0 0.5 1.0 1.5

MgB2

normalized conductance

Normalized bias voltage

• 4
• 3
• 2
• 1

1 2 3 4 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

T = 0.15 K

Bias voltage (mV)

ErNi2B2C Tc=11K

Normalized conductance

• 2
• 1

1 2 0.0 0.5 1.0 1.5 2.0

Tc=1.85 K PrOs4Sb12 Normalized conductance Bias voltage / 0 ( = 1.73kBTc)

The superconducting gap through scanning tunneling spectroscopy at very low temperatures

Uemura plot

Multiband Elements UPt3 PrOs4Sb12 Sr2RuO4 MgB2 Al TaS2 NbSe2 LuNi2B2C

Sr2RuO4 YNi2B2C ErNi2B2C MgB2 NbS2 NbSe2

TaS2

dE V eV E f E N dV dI      ) ( ) (

Madrid

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Quasiparticle interference

𝜍 𝑠 = 𝑑𝑝𝑡 2𝑙𝐺𝑠 𝑠3

1 2 3 4 5 6 10 20 30

Height (pm) Lateral Position (nm)

1.3nm

Atomic resolution STM

Here: URu2Si2 at 150 mK

Electronic standing waves

     

F F

E N E E I , d d

2

  

  

  lF a

Can we find atomic resolution in a metal ?

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Atomic resolution

• K. Cho et al Phys Rev B, 95, 100502(R) (2017)



 

i i 2 i 2 S

(k) Δ E E (E) N 

• 15
• 10
• 5

5 10 15 0,0 0,5 1,0 1,5

Normalized conductance

Bias voltage (mV)

• 15
• 10
• 5

5 10 15 0,0 0,5 1,0 1,5

Normalized conductance

Bias voltage (mV)

22 21 21 22

i



(k) Δi (k) Δi

i



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𝜍 𝑠 = 𝑑𝑝𝑡 2𝑙𝐺𝑠 𝑠3

1 2 3 4 5 6 10 20 30

Height (pm) Lateral Position (nm)

1.3nm

Atomic resolution STM

Here: URu2Si2 at 150 mK

Electronic standing waves

     

F F

E N E E I , d d

2

  

  

 

lF a

Quasiparticle interference

Can we find atomic resolution in a metal ?

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Energy, bias voltage Wavevector

Direct imaging of the two-dimensional Fermi contour: Fourier-transform STM

• L. Petersen et al.
• Phys. Rev. B, R6858, 57 (1998)

A phenomenological approach of joint density of states for the determination of bandstructure in the case of a semi-metal studied by FT-STS

• L. Simon, F. Vonau and D. Aubel
• J. Phys. Cond. Matt. 19 (2007) 355009

Real space conductance map Fourier transform EF

2kF 2kF

½ lF

Fermi surface Real space DOS

Quasiparticle interference Bandstructure of empty and filled states

Real space DOS Fermi surface

QPI

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Energy, bias voltage Wavevector

Direct imaging of the two-dimensional Fermi contour: Fourier-transform STM

• L. Petersen et al.
• Phys. Rev. B, R6858, 57 (1998)

A phenomenological approach of joint density of states for the determination of bandstructure in the case of a semi-metal studied by FT-STS

• L. Simon, F. Vonau and D. Aubel
• J. Phys. Cond. Matt. 19 (2007) 355009

Real space conductance map Fourier transform EF

2kF 2kF

½ lF

Fermi surface Real space DOS

Quasiparticle interference Bandstructure of empty and filled states

Real space DOS Fermi surface

𝑕 𝐹, 𝑟 ∝ 𝑊

𝑡

𝑟

2𝐾 𝐹,

𝑟 𝐾(𝐹, 𝑟) ∝ 𝑂1 𝐹, 𝑙1 𝑂2 𝐹, 𝑙2

QPI

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Energy, bias voltage Wavevector EF

2kF

Spectroscopic scanning tunneling microscopy insights into Fe-based superconductors

• J. Hoffman Rep. Prog. Phys. 74 (2011) 124103

Anisotropic energy gaps of iron-based superconductivity from intraband quasiparticle scattering in LiFeAs Science 336 (2012) 563

Quasiparticle interference Superconducting gap anisotropy

E k e(k) e(k) kF 

• kF

𝜁 𝑙 2 + Δ2

QPI

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H T

T

c

Hc1 Hc2 Hc Meissner state Mixed state Normal phase

H

Meissner state Mixed state

H

d

H(T) / 50 d(nm) 

r

s 2

n Ψ  H

l



J J

Type II superconductors : high upper critical field + the vortex lattice

2 2

2  

c

H



 

i

e 

  

 

, , k k   

 

2 2

) (    E E E N

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r ns(r) H(r) r E

|∆|

Bound core states: Caroli-de Gennes-Matricon states 

S N S

Current carried by bound states of superconducting vortices

• D. Rainer, J.A. Sauls and D. Waxmann
• Phys. Rev. B, 54, (1996)

The vortex physics which comes from the vortex core N.B. Kopnin

• Physica. B, 280, 231, (2000)

M.P. Gonzalez, J. Villlegas,

• E. Gonzalez and J.L. Vicent,

Vórtices en superconductores, Inv y Ciencia, vol. 369 (2016)

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• 2
• 1

1 2 0.0 0.5 1.0 1.5 Normalized conductance

Bias Voltage (mV)

• 2
• 1

1 2 0.0 0.5 1.0 1.5

Normalized conductance Bias voltage (mV)

0 mV 0.3 mV 0.5 mV

NbSe2 NbS2

Internal electronic structure of the vortex cores: NbSe2 vs. NbS2

Superconducting density of states and vortex cores in NbS2

• I. Guillamon, H. Suderow, S. Vieira and P. Rodiere

Phys Rev Lett, 101, 166407 (2008) IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 21

Shape of the vortex core depends on bandstructure and gap symmetry 𝝄 = ℏ𝒘𝑮 𝝆𝜠 𝒘𝑮 = 𝒘𝑮 𝑮𝑻= 𝒆𝒜𝒆𝜾 𝑶 𝒜, 𝜾 𝒘𝑮 𝜠 = 𝜠 𝜾

r

s 2

n Ψ  H

l 

J J Theory of quasiparticle bound states in iron-based superconductors: application to scanning tunneling spectroscopy of LiFeAs

• Y. Wang, P.J. Hirschfeld and I. Vekhter

Phys Rev B, 85, 020506(R) (2012) Angular band structure of a vortex line in a type II superconductor

• F. Gygi and M. Schluter
• Phys. Rev. Lett., 65, 1820 (1990)

Star shaped local density of states around vortices in a type II superconductor

• M. Ichioka, N. Hayashi and K. Machida
• Phys. Rev. Lett. 77, 4074 (1996)

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High Tc materials: Geneva , Paris, Tokyo/Nagoya, Cornell , Princeton, … Nickel borocarbides Tokyo/Nagoya, Argonne, Madrid FeAs, FeSe Beijing, Harvard, Tokyo … Heavy fermions Princeton, Cornell

Vortex cores in perpendicular fields by STM

Scanning tunneling spectroscopy of high-temperature superconductors

• O. Fischer, M. Kugler, I. Maggio-Aprile, Ch. Berthod

Rev Mod Phys, 79, 373 (2007) Imaging superconducting vortex cores and lattices with a STM

• H. Suderow, I. Guillamón, J.G. Rodrigo and S. Vieira
• Superc. Sci. Techn., 27, 063001 (2014)

Very thin films Paris, …

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Vortex cores in tilted fields by STM

Subsurface bending and reorientation of tilted vortex lattices in bulk isotropic superconductors due to Coulomb-like repulsion at the surface

• E. Herrera et al,Phys Rev B, 96, 184502 (2017)

Tilted vortex cores and superconducting gap anisotropy in 2H-NbSe2 J.A. Galvis et al, Comm. Phys. 2:31 (2019) Lateral imaging of the superconducting vortex lattice using Doppler-modulated scanning tunneling microscopy, I. Fridman et al, Appl. Phys. Lett. 99, 192505 (2011) IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 24

S S Cooper pair tunneling I

• 0.4
• 0.2

• 4
• 2

Conductance (M

• 1)

Voltage (mV)

Superconducting tip: Josephson Josephson

S S eV=0



 

i

e 

L



R



R L

    

) sin(  I I  V e t  2   

) sin(  I I 

Density of Cooper pairs ns1 and ns2 Phase ?

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Quantum phase as a measurable quantity: DC and AC Josephson effect

S1 S2

2 1 , 1 1 , 1

1

 



  

S i

n e

2 2 , 2 2 , 2

2

 



  

S i

n e

cte x x n cte j n j

s S s S

      ) ( A I    I A    

s m e s S

n en j

 S

v 2

https://nanocohybri.inc.uam.es/wp-content/uploads/2019/01/Koelle_1.pdf

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) sin(  I I 

First Josephson equation

Quantum phase as a measurable quantity: DC and AC Josephson effect

S1 S2

I A I V

e V   2

I

Coherent current V=0

V e t  2   

Second Josephson equation

V

 

t V t 2 F      ) 2 sin( t V I I F    

2 F  V

J

 

V mV GHz

J

6 . 483 2  

 

  

F  F         2 2 sin C R I t I I

n

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Josephson effect at atomic level EJ -> Junction resistance << 𝒍𝑪T about 0.1 K I V

e V   2

I

Coherent current V=0

V mV GHz

J

6 . 483 2   IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 28

• Real space imaging and spectroscopy
• Atomic structure
• Electronic bandstructure
• Superconducting gap structure
• Vortex lattice structure
• Josephson effect (phase)
• Pairing interaction
• Electronic correlations (Coulomb, Kondo)

Real space visualization of electronic correlations

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• Real space imaging and spectroscopy of the vortex lattice
• Superconducting CaKFe4As4, bandstructure, vortex core, vortex lattice

and pinning

• Vortex lattice structure: interactions vs disorder
• Observation of vortex creep on cooling
• Josephson effect at atomic scale

Real space imaging of the superconducting vortex lattice: Recent results and prospects

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 30

2 m

100 mK 13 eV

100mK, 50 mK, 10 mK, 30 mK Patente

Tip and sample preparation and scanning window Small compact dil fridge STM/S

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dE V eV E f E N dV dI

S

     ) ( ) ( 15eV

) , ; ( y x E NS

• 1.0
• 0.5

0.0 0.5 1.0 0.0 0.5 1.0 1.5 2.0

Experiment BCS  = 0.2 meV T = 0.1 K

Normalized conductance Bias voltage (mV) Al-Au

Temperature

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15 V  183mK

Energy resolution

• 900
• 600
• 300

300 600 900 2 4 6 8 10 Al-Al T=0.19 K Tc=1.2 K

normalized conductance Bias voltage (V)

• 600
• 300 0

300 600

• 1.0
• 0.5

0.0 0.5 1.0 current (nA) Bias voltage (V)

S-S

• 10
• 5

5 10 2 4 6 8 10

Pb-Pb T=0.5K Tc=7.2K normalized conductance Bias voltage (mV)

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3D printed in grade 5 Titanium alloy

New smaller STM/S

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STM/S in Madrid

Very high magnetic field STM (22 T), Isabel Guillamón Isabel.guillamon@uam.es

22 T superconducting coil, hundreds of field ramps and no single quench in Madrid

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aterials

Q

-Bi2Pd

Shiba states on Cr adatoms

Influence of Magnetic Ordering between Cr Adatoms on the Yu-Shiba-Rusinov States

• f the β-Bi2Pd Superconductor

DJ Choi et al PRL 120 (2018) 167001

• J. Zaldivar, J.I. Pascual

Superconductivity at 5.4 K in -Bi2Pd

• Y. Imai JPSJ 81, 113708

Full gap superconductivity in spin- polarised surface states of topological semimetal -Bi2Pd

• K. Iwaya Nat Comm, 8, 976 (2017)

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• Real space imaging and spectroscopy of the vortex lattice
• Superconducting CaKFe4As4, bandstructure, vortex core, vortex lattice

and pinning

• Vortex lattice structure: interactions vs disorder
• Observation of vortex creep on cooling
• Josephson effect at atomic scale

Real space imaging of the superconducting vortex lattice: Recent results and prospects

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 37

Fe As / Se Li Sr La/Sr O / F Sc

Crystal structures in the iron pnictides

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Critical temperature and magnetic field

Potentials of iron-based superconducting alloys for practical future materials J.I. Shimoyama

• Superc. Sci. Tech., 044002, 27 (2014)

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The CaKFe4As4 system

• Wed. Afternoon

PC5-4, Unique defect structure and advantageous vortex pinning properties in CaKFe4As4, Ishida PC5-5, Critical current density and its enhancement by particle irradiation in CaK2Fe4As4F2, Tamegai

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Topography of CaKFe4As4: No surface reconstruction Ca-K surface with stripes

White scale bar: 20 nm

The CaKFe4As4 system

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Two gap superconductivity in CaKFe4As4, Tc = 35 K Stripes The CaKFe4As4 system

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Two gap superconductivity in CaKFe4As4, Tc = 35 K Stripes



 

i i 2 i 2 S

(k) Δ E E (E) N 

∆ = ∆(k)

The CaKFe4As4 system

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Two gap superconductivity in CaKFe4As4, Tc = 35 K London penetration depth, R. Prozorov et al

∆

2

∆

1

• K. Cho et al, PRB, 95, 100502(R) (2017)

1 2

The CaKFe4As4 system

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Quasiparticle interference scattering

15 nm

Topography Spectroscopy Spectroscopy Spectroscopy

The CaKFe4As4 system

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Quasiparticle interference scattering

Topography Spectroscopy Fourier transform of the spectroscopy

4 mV

15 nm

The CaKFe4As4 system

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 46

Fourier transform of the spectroscopy

• One main scattering wavevector whose

size increases with energy

• No scattering below about 4 mV

The CaKFe4As4 system

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 47

Mou et al., PRL 117 277001 (2016)

   

ARPES The CaKFe4As4 system

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 48

Electron dispersion relation from quasiparticle interference scattering Empty and full states. Innermost pocket closes a few mV above EF The CaKFe4As4 system

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Superconducting gap opening from quasiparticle interference scattering Isotropic gap opening in the hole sheets The CaKFe4As4 system

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Superconducting gap opening from quasiparticle interference scattering Zero bias DOS ?? The CaKFe4As4 system

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Quasiparticle interference scattering at zero bias within the superconducting gap

15 nm

Topography Spectroscopy Spectroscopy Spectroscopy

The CaKFe4As4 system

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 52

Zero bias states and pinning

1.2

1 10 20 40 60 80

Distance (nm) Field (T)

1 T 3 T 5 T 2 T 4 T 6 T 8 T

The CaKFe4As4 system

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Using de Gennes relation to understand N(r) in a vortex core

Field dependence of the vortex core size V.G. Kogan and N.V. Zhelezina,

• Phys. Rev. B, 71, 134505 (2005).

r E

|∆|

r E

|∆|

r E

|∆|

0.3 T 70 nm

Increasing H

d/dr  1 / C H d/dr  1 / C H d/dr  1 / (C Hc20

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0,0 0,2 0,4 0,6 0,8 1,0 0,0 0,2 0,4 0,6 0,8 1,0

Mean radial avg Kogan fit for: B = 0.25 T  = 0.8

• Norm. Conductance (a.u.)
• Norm. Distance (r/a)

Applied to different superconductors

Rh4In4S4 CaKFe4As4 PRB 97, 134501 (2018) PRB 95, 134505 (2017)

• Comm. Phys. (2018) 1:30

NbSe2 NbSe1.2S0.8

Field dependence of the vortex core size probed by STM

• A. Fente et al, Phys. Rev. B, 94, 014517 (2016)

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Pair breaking and vortex pinning in CaKFe4As4 Core size C <-> size of pair breaking features Single vortex pinning The CaKFe4As4 system

Field dependence of the vortex core size probed by STM

• A. Fente et al, Phys. Rev. B, 94, 014517 (2016)

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Disordered vortex lattice

Red: Vortex with five nearest neighbors Black: Vortex with seven nearest neighbors

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• Real space imaging and spectroscopy of the vortex lattice
• Superconducting CaKFe4As4, bandstructure, vortex core, vortex lattice

and pinning

• Vortex lattice structure: interactions vs disorder
• Observation of vortex creep on cooling
• Josephson effect at atomic scale

Real space imaging of the superconducting vortex lattice: Recent results and prospects

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 58

TC = 7.2 K

T HC 2 . 4

2  

T HC 7 . 12

2



3

2 2

   

 

 

C C

H H

• T. Janssen et al. Phys. Rev. B. 57, 11698 (1998)
• R. C. Morriset al. Phys. Rev. B. 5, 895 (1972)

Upper critical field of the anisotropic superconductor 2H-NbSe2

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2H-NbSe2: Vortex lattice in tilted magnetic fields

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2H-NbSe2: Vortex lattices spontaneously move sometimes in tilted magnetic fields Slow vortex creep Washboard potential

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Creeping lattices when cooling Increasing temperature stops creep Decreasing temperature again -> creep restarts

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 62

Increasing temperature stops creep Decreasing temperature again -> creep restarts

• R. Willa

(Wednesday, 10h30, PC3-1)

Creeping lattices when cooling

Thermal creep emerging from cooling a tilted vortex lattice in uniaxial superconductor

• R. Willa et al, arxiv 1906.06294

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 63

• Real space imaging and spectroscopy of the vortex lattice
• Superconducting CaKFe4As4, bandstructure, vortex core, vortex lattice

and pinning

• Vortex lattice structure: interactions vs disorder
• Observation of vortex creep on cooling
• Josephson effect at atomic scale

Real space imaging of the superconducting vortex lattice: Recent results and prospects

IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 64

• W. Meier, S. Bud’ko and P.C. Canfield

V.G. Kogan Ames Lab

Thank you very much for your attention

• V. Barrena, F. Martín Vega
• E. Herrera, J. Benito
• B. Wu

J.G. Rodrigo, S. Vieira

• C. Munuera, F. Mompean and M. García-Hernández

ICMM-CSIC

• I. Guillamón
• A. I. Buzdin

Bordeaux

• S. Park, A. Martín, A. Levy-Yeyati
• J. Herrera William

Bogotá

• D. Aoki, G. Knebel, JP Brison and J Flouquet

Grenoble

• K. Kadowaki

Tsukuba

• Y. Anahory, Weizmann, Hebrew University
• Y. Fasano, Bariloche
• M. Milosevic, Antwerp

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36 Member States: Austria, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Montenegro, The Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom, the former Yugoslav Republic of Macedonia and One cooperating state: Israel

www.nanocohybri.eu 26 states

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www.nanocohybri.eu Dimitri Roditchev and Brigitte Leridon, March 2018 Yony Anahory and Beena Kalisky, February 2019 IEEE CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), February 2020. Plenary presentation PL1-INV given at ISS, 3-5 December 2019, Kyoto, Japan. 67

• Open network
• Meetings (2/year)
• Short term stays

www.nanocohybri.eu

https://www.cost.eu/actions/CA16218/#tabs| Name:management-committee

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Short term stays

www.nanocohybri.eu

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