Los Alamos National Lab Filip Ronning Operated by Los Alamos - PowerPoint PPT Presentation

The “115” Superconductors Eric Bauer Fedor Balakirev Xin Lu Marc Janoschek Roman Movshovich Joe Thompson Vladamir Sidorov Jianxin Zhu (LANL) Soonbeom Seo Tuson Park (SKKU) Zach Fisk (UC Irvine) Philip Moll (ETH) Hiro Sakai (JAEA) Hiroshi Yasuoka (JAEA) Luis Balicas (NHMFL) Los Alamos National Lab Filip Ronning Operated by Los Alamos National Security, LLC for NNSA

Outline: • 115 heavy fermion primer • Non-universality of dopants (Cd vs. Sn doping) • Influence on quantum criticality and superconductivity • High Magnetic Field Study of CeRhIn5 • Competing Density wave • Gigantic anisotropy Operated by Los Alamos National Security, LLC for NNSA

Superconductivity in Heavy Fermions • • Large entropy goes Stoichiometric → high purity, into the SC state large m.f.p. (> 1 µ m) 2.0 CeCoIn 5 H=0 T 1.5 CeCoIn 5 H=9 T C/T (J/mol-K 2 ) LaCoIn 5 • Heavy 1.0 Electrons • Dirac C ∝ Materials * m 0.5 T • Nodal QP’s • small energy 0.0 • that are heavy scale → highly 0 2 4 6 8 10 tunable T (K) • T c /T F similar to cuprates Operated by Los Alamos National Security, LLC for NNSA

SC in proximity to Antiferromagnetism Monthoux , Pines, & Lonzarich , Nature ‘07 Nandi, Canfield , et al, PRL ‘10 CeCoIn 5 • Phase diagram generic for Cerium heavy fermion SC’s • Parent compound is an AF metal • T c /T F ~ 0.1 • SC is unconventional (power laws/sign changing OP) • Tunable with doping or pressure. • Spin Fluctuations… Operated by Los Alamos National Security, LLC for NNSA

Reducing ¡Dimensionality ¡ CeM 2 In 7 Ce 2 MIn 8 CeMIn 5 13 compounds in Increasing ¡Bandwidth ¡ this family are CeIn 3 superconductors T c = 0.2 K T c = 2.3 K T c = 2.1 K NpPd 5 Al 2 T c = 5 K PuMGa 5 T c = 18.5 K Operated by Los Alamos National Security, LLC for NNSA

Cd d vs Sn n doping doping in in the he 115’ 115’s A Tale ale of of Two o Dopant opants Why doping? Dopants provides a window into novel states of matter Operated by Los Alamos National Security, LLC for NNSA

How we identified the instability in CeCoIn 5 T c 5 CeRhIn 5 T N 4 ~ CeCoIn 5 3 T (K) AFM 2 SC 1 AFM+ SC 0 0.0 0.5 1.0 1.5 2.0 2.5 P (GPa) Cd doping ~ <decreases hybridization> Sn doping ~ <increases hybridization> CeRhIn 5 CeRh(In,Sn) 5 CeCo(In,Cd) 5 (P) (P) (P) Operated by Los Alamos National Security, LLC for NNSA H. Hegger, et al. PRL (2000); L. Pham, et al. PRL (2006); E.D. Bauer, et al. PRB (2006)

Cd versus Sn doping 5 CeCo(In,Cd) 5 4 3 T (K) 2 AFM SC 1 AFM SC 0 0.0 P c1 1.0 2.0 P (GPa) 100 ρ (P)/ ρ (2.46) T max 2.00 Temperature (K) 1.45 10 0.900 AFM SC 0.0 P c1 1.0 2.0 Pressure (GPa) CeRhIn 5 CeRh(In,Sn) 5 CeCo(In,Cd) 5 Operated by Los Alamos National Security, LLC for NNSA T. Park, et al . Nature ’08 S. Seo, et al . Nat. Comm. ’15 S. Seo, et al . Nat. Phys. ’13

Cd versus Sn doping Cd doping: § Decreased hybridization § Small Tc suppression § Signature of QCP disappears. Sn doping: § Increased hybridization § Larger Tc suppression § Signature of QCP remains. Operated by Los Alamos National Security, LLC for NNSA

NMR A(Bulk) C B D Cd = “AFM droplets” Sn ≈ homogeneous H. Sakai, et al . unpublished Operated by Los Alamos National Security, LLC for NNSA

Robustness to impurity scattering: CeCoIn 5 K. Gofryk, et al PRL ‘12 0.1 0.26 0.4 ξ 0 / l Little doubt that this system is d x2-y2 . Robustness likely due to strong coupling and extreme multiband. Are inhomogeneous dopants less pair-breaking than homogeneous ones? Are filled shells less pair breaking (ie. Cd and Zn)? Operated by Los Alamos National Security, LLC for NNSA Inhomogeneity can obscure signatures of criticality!

Quantum Criticality in Pnictides BaFe 2 (As,P) 2 Ba(Fe,Co) 2 As 2 K. Hashimoto, et al. Science ‘10 v QC not always so apparent in pnictides (QC scaling removed by disorder?) F. Ning, T. Imai, et al. JPSJ ‘09 v SC still robust. Operated by Los Alamos National Security, LLC for NNSA

Acces ccessing ing the he AFM FM QC QCP wit ith h ma magnet gnetic ic field ield Operated by Los Alamos National Security, LLC for NNSA

A field induced density wave in CeRhIn 5 Phase boundaries from T. Park, NJP (2009) and L. Jiao, et al. PNAS (2015) Operated by Los Alamos National Security, LLC for NNSA P. Moll, et al. Nat. Comm. (in press)

Microstructured CeRhIn 5 50 um v Enables magnetoresistance at high fields v High current densities possible RRR ~ 260 v Transport anisotropy of small crystals Operated by Los Alamos National Security, LLC for NNSA P. Moll, et al. Nat. Comm. (in press)

A field induced density wave in CeRhIn 5 v Field induced transition within the AFM state v Hysteresis vanishes in pulsed fields. Operated by Los Alamos National Security, LLC for NNSA P. Moll, et al. Nat. Comm. (in press)

A field induced density wave in CeRhIn 5 v Not clearly observed in M(H) or R c (H) v Small fraction of the Fermi surface participates Operated by Los Alamos National Security, LLC for NNSA P. Moll, et al. Nat. Comm. (in press)

A field induced density wave in CeRhIn 5 v I-V curves resemble CDW systems Operated by Los Alamos National Security, LLC for NNSA P. Moll, et al. Nat. Comm. (in press)

Angular dependence of the density wave state v Pushing field into the ab-plane makes the density wave formation energetically unfavorable. Operated by Los Alamos National Security, LLC for NNSA P. Moll, et al. Nat. Comm. (in press)

Fermi surface topology change P. Moll, et al. Nat. Comm. (in press) L. Jiao, et al . PNAS (2015) Operated by Los Alamos National Security, LLC for NNSA

Similarity with cuprates Compet ompeting ing Phas hases es B. Keimer, et al. ArXiv: 1409.4673 A field induced density wave Operated by Los Alamos National Security, LLC for NNSA

Anomalous transport with H//ab Operated by Los Alamos National Security, LLC for NNSA

Spin Waves in CeRhIn 5 J 0 = ¡0.37 ¡meV, ¡ ¡ J 1 ¡ = ¡0.05 ¡meV ¡ J 2 ¡= ¡0.809 ¡ J 1 ¡ Δ ¡= ¡0.82 ¡ The ¡existence ¡of ¡a ¡spin ¡gap, ¡ ¡ Δ sg ¡= ¡0.25 ¡meV , ¡is ¡ unexpected ¡for ¡the ¡ordered ¡ Q ¡ = ¡(½, ¡½, ¡ 0.297 ) ¡moments. ¡ CeRhIn 5 is a frustrated system along the c-axis Operated by Los Alamos National Security, LLC for NNSA P. Das, et al. PRL (2014)

Spin-Or pin-Orbit bit Coupling oupling Operated by Los Alamos National Security, LLC for NNSA

How does Spin-Orbit coupling influence T c ? Co 2.5 Rh Ce M In 5 2.0 Max T c 1.5 Ir 1.0 0.5 0.0 4 /n 3 ~ λ SO Z Y. Chen, et al . (unpublished) Operated by Los Alamos National Security, LLC for NNSA

Summary ¡ � two non-magnetic dopants (Cd and Sn) produce dramatically different responses. � Inhomogeneity can have weaker pair breaking effects � Can also disguise signatures of quantum criticality � Field Induced Density Wave in CeRhIn5 under applied magnetic field � How does spin-orbit coupling influence Tc? Operated by Los Alamos National Security, LLC for NNSA

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