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What is special for bad actors ? – Bond angle

This article discusses the relationship between bond angle and electronic correlations in "bad actors" and their impact on superconductivity. It explores the correlation diagram and evolution of electronic phases with correlation strength in various materials.

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What is special for bad actors ? – Bond angle

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  1. What is special for bad actors ? – Bond angle 1UC FeSe Ba0.6K0.4Fe2As2 LiFeAs FeSe KFe2As2 C.H. Lee, A. Iyo, H. Eisaki et al., J. Phys. Soc. Jpn. 77, 83704 (2008).

  2. The smaller bond angle (larger Pn/Ch height) points toward stronger electronic correlations in bad actors.

  3. Correlation diagram: Bond angle vs electron filling ‘Correlation’ diagram for 122-Fe pnictides family Smaller abondnarrower band widthstronger correlation M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  4. Correlation diagram: Bond angle vs electron filling ‘Correlation’ diagram for 122-Fe pnictides family Smaller abond narrower band width stronger correlation 3d 5 half-filled Stronger correlation toward d 5: half-filling, maximal correlation M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  5. Correlation diagram: Bond angle vs electron filling The smaller bond angle (larger Pn/Ch height) and lower electron filling (d6d5) point toward stronger electronic correlations in bad actors.

  6. Correlation diagram: Bond angle vs electron filling Evolution of dominant electronic phases with correlation strength paramagnetic metal / conventional SC SDW / unconventional SC magnetic order M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  7. Doping: Change of Correlation Doping links TM pnictides with different correlation strengths. M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  8. Relationship between Correlation Strength and SC Doping links TM pnictides with different correlation strengths, and unconventional SC emerges in the region between the two dashed lines. M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  9. Correlation diagram: Region of unconventional SC Evolution of dominant electronic phases with correlation strength paramagnetic metal / conventional SC SDW / unconventional SC magnetic order M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  10. Relationship between Correlation Strength and SC High-Tc SC emerges when correlations are not too weak nor too strong. optimal Tc M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  11. Relationship between Correlation Strength and SC Highest Tc is in the ‘ intermediate coupling’ region. Ba0.6K0.4Fe2As2 1111 optimal Tc M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  12. Bad actors/good actors on the correlation diagram Bad actors (in yellow) have marginally strong correlation. Ba0.6K0.4Fe2As2 LiFeAs Bad actors FeSe M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  13. ‘Bad’ actors (4): ‘Good’ or ‘Bad’ Are Fe(Se,Te)and Ba0.6K0.4Fe2As2 really good actors ? Bulk FeSe looks a bad actor,but how about the monolayer FeSe ? Ba0.6K0.4Fe2As2 ? Fe(Se, Te) ? FeSe monolayer ? g ky (p/a) a b kx (p/a)

  14. ‘Bad’ actors (4): ‘Good’ or ‘Bad’ Fe(Se,Te)and Ba0.6K0.4Fe2As2 (in orange) on the correlation diagram Ba0.6K0.4Fe2As2 good actor LiFeAs Bad actors FeSe Fe(Se,Te) M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  15. ‘Bad’ actors (4): ‘Good’ or ‘Bad’ Why does Fe(Se,Te)appear to be a good actor ? Fe(Se, Te) ? The presence of a single h-FS and a single e-FS with simple orbital character might be a reason ?

  16. ARPES-Ba0.6K0.4Fe2As2: An evidence for a good actor ? Ba0.6K0.4Fe2As2 H. Ding et al., Europhys. Lett. 83, 47001 (2008); K. Nakayama et al., ibid. 85, 67002 (2009). D(k) = D0 coskx cosky (s±) +D0 g ky (p/a) a b The gap magnitude is larger on the inner FS. -D0 kx (p/a)

  17. A Bad actor (4): Orbital antiphase s± pairing ? Ba0.6K0.4Fe2As2 dxz/dyz–dxy antiphase s± symmetry The SC order parameter changes sign within the hole-FS and within electron-FS: + Max 0 - Max An ab initio calculation based on DMFT & DFT Z.P. Yin, K. Haule & G. Kotliar, Nature Phys. 10, 845 (2014).

  18. Sign-reversal of D between hole (electron) FS pockets in Ba0.6K0.4Fe2As2 ARPES observation of momentum-confined in-gap impurity state in Ba0.6K0.4Fe2As2 may be a signature of the sign-reversal. P. Zhang, J.P. Hu, H. Ding et al., Phys. Rev. X4, 031001 (2014). impurity state + Max 0 - Max Z.P. Yin, K. Haule & G. Kotliar, Nature Phys. 10, 845 (2014).

  19. Monolayer FeSe on STO vs bulk FeSe Enhancement of Tc in FeSe either by electron doping or by increasing a Bad actor FeSe M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  20. Monolayer FeSe on STO vs bulk FeSe Monolayer FeSe on STO appears to be a good actor on the correlation diagram. monolayer FeSe FeSe M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  21. Anisotropic but fully gapped FS: Orbital-selective pairing in monolayer FeSe dxy FeSe monolayer dxz Y. Zhang, D.-H. Lee, Z.-X. Shen et al., PRL 117, 117001 (2016). dxy dxy dxy dyz Largest gap on the dxy- FS, at the ellipse tip cf.The largest gaps on dxz/dyz in LiFeAs, FeSe, and KFe2As2 A. Kreisel, P. Hirschfeld et al., arXiv:1611.02643.

  22. d-wave orbital-triplet s± pairing in FeSe monolayer ? fully gapped e-FS FeSe monolayer Y. Zhang, D.-H. Lee, Z.-X. Shen et al., PRL 117, 117001 (2016). d-wave orbital triplet s±pairing Largest gap at the ellipse sides Largest gap at the ellipse tip T. Ong, P. Coleman, J. Schmalian, PNAS 113, 5486 (2016).

  23. ‘Good’ actors vs ‘Bad’ actors The smaller bond angle (larger Pn/Ch height) and lower electron filling (d6d5) point toward stronger electronic correlations in bad actors. To understand the bad actors (4), ‘orbital-selectiveness’ needs to be incorpolated: e.g. “The electronic correlations are stronger on thedxyorbital with respect to thedxzanddyzorbitals.”

  24. Correlation diagram: Orbital selective electron filling The correlation diagram should be modified by taking ‘orbital-specific’ filling into account. dxy dyz dxz dz2 dx2-y2 dxy dyz dxz dz2 dx2-y2 M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  25. ‘Good’ actors vs ‘Bad’ actors: Summary + Max 0 Good actors with conventional s± pairing are rare. - Max Conventional s±seems to be a fortuitous case where contributions from all orbitals have equal sign. “A new paradigm” after 2011 “Unconventional SC + orbital physics such as orbital-antiphase s± pairing may be the state unifying all families of Fe-based superconductors.”

  26. Extended phase diagram: Double SC/AF domes L. Sun, Z.-X. Zhao et al., Nature 483, 67 (2012). electron doping PT AFO M.. Hiraishi, K.M. Kojima et al., Nature Phys. 10, 300 (2014). isovalent doping PT AFO hole doping PT AFO K.T. Lai, S. Tajima et al., PRB 90, 064504 (2014).

  27. Ubiquitous double SC/AF domes KFe2As2 @ P FeSe @ P nematic AF FS reconstruction SC2 SC1 Y. Nakajima, J. Paglione et al., PRB 91, 060508(R) (2015). T. Terashima et al., PRB 93, 094505 (2016).

  28. Ubiquitous double SC/AF domes Tc in metal-ammoniated FeSe is sensitive to c / Se-height / a . (NH3)yCs0.4FeSe @ P (NH3)yMxFeSe M. Izumi, Y. Kubozono et al., Sci. Rep. 5, 9477 (2015). L. Zheng, Y. Kubozono et al., Sci. Rep. 5, 12774 (2015). Collapsed tetragonal, FS reconstruction, and structural modification all point towarda change in the 3d-levels configuration and hence in the electron filling in relevant 3d orbital levels.

  29. Correlation diagram: Orbital selective electron filling Pressure/Doping: Local structural modification and change in electron filling Possible change in the 3d-levels configuration and hence in the electron filling in relevant 3d orbital levels 3d 6+d 3d 6 dxy dxy dyz dxz dyz dxz dz2 dz2 dx2-y2 dx2-y2 AF2/SC2 AF1/SC1 M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  30. Double SC/AF domes: Orbital-selectiveness C.-Y. Moon, K. Haule et al., Phys. Rev. B 94, 224511 (2016). D.-Y. Liu et al., arXiv: 1701.02500 Activated xy orbital in the AF2/SC2 domes in the high-doping region LaFeAsO1-xHx LaFeAs1-xPxO n = 6 n = 6.5 n = 6 n = 6 xy xy xy xy xz xz yz yz xz yz xz yz z2 z2 z2 z2 x2- y2 x2- y2 x2- y2 x2- y2 M. Hiraishi, K.M. Kojima, H. Hosono et al., Nature Phys. 10, 300 (2014). K.T. Lai, S. Tajima et al., Phys. Rev. B 90, 064504 (2014).

  31. Supplementary Informations

  32. Coherent and incoherent ‘Drude’ components in optical conductivity M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  33. Fraction of incoherent Drude weights in various TM pnictides incoherent metal coherent metal Fe(Se, Te) KFe2As2 BaNi2As2 BaCo2As2 BaNi2P2 BaMn2As2 BaFe2As2 BaFe2P2 (La, Sr)2CuO4 ND / Neff 0 0.10 0.20 0.30 0.40 M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

  34. Fraction of incoherent weights is a measure of correlations incoherent metal coherent metal Fe(Se, Te) KFe2As2 BaNi2As2 BaCo2As2 BaNi2P2 BaMn2As2 BaFe2As2 BaFe2P2 (La, Sr)2CuO4 ND / Neff 0 0.10 0.20 0.30 0.40 M. Nakajima et al., J. Phys. Soc. Jpn. 83, 104703 (2014).

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