arpes studies of unconventional
DESCRIPTION
Phase diagrams pnictide SC heavy fermion SC organic SC cuprate SCTRANSCRIPT
![Page 1: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/1.jpg)
Hong Ding
Institute of Physics, Chinese Academy of Sciences
ARPES studies of unconventionalsuperconductors
Heavy Fermion Physics Workshop, January 9, 2012
![Page 2: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/2.jpg)
Phase diagrams
cuprate SC
pnictide SC
organic SC
heavy fermion SC
![Page 3: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/3.jpg)
0.4
0.3
0.2
0.1
0
0.4
0.3
0.2
0.1
0
Momentum
0
0
-π
π
Unoccupiedstates
Occupied statesBinding energy (eV)
Binding energy (eV)
Fermi surface mapping of cuprates
Tight binding fitting
Large FS, area = 1-x: Luttinger’s theorem
Bi2Sr2CaCu2O8
![Page 4: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/4.jpg)
d-wave superconducting gap in cuprates
dx2-y2 + +
-
-
θ
0
10
20
30
40
0 20 40 60 80FS angle
115
MMΓ
Y1 15Half-Integer Flux Quantum Effect
![Page 5: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/5.jpg)
0.2 0.1 0.0 -0.1 0.2 0.1 0.0 -0.1 0.2 0.1 0.0 -0.1
0.2 0.1 0.0 -0.1 0.2 0.1 0.0 -0.1 0.2 0.1 0.0 -0.1Binding Energy (eV)
14K 40K 70K
200K120K90K
Tc = 83 K, at Fermi surface along M-Y
pseudogapT* = 170K
Pseudogap in underdoped cuprates
0
100
Doping (e/Cu)
Temperature
AFM S.C.State
underdopedoverdoped
![Page 6: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/6.jpg)
Phase diagram of Ba122 system
Hole doping
Electron doping
Electron-hole asymmetry?M. Neupane et al., PRB 83, 094522 (2011)
![Page 7: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/7.jpg)
ARPES observation of five bands and five FSs
![Page 8: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/8.jpg)
Fermi surface evolution in “122”
Electron doping
Hole dopingParent
Heavily OD Slightly OD OPT UD
OPTUD Heavily OD
Tc = 3 K Tc = 22 K Tc = 37 K Tc = 26 K
Tc = 0 K Tc = 11 K Tc = 25 K Tc = 0 KTN = 135 K
QAF QAF QAF QAF
QAFQAF QAF
8
![Page 9: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/9.jpg)
ARPES observation of superconducting gap
2/Tc ~ 7H. Ding et al., EPL 83, 47001 (2008)
![Page 10: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/10.jpg)
Nodeless SC gap in Ba0.6K0.4Fe2As2 (Tc = 37K)
K. Nakayama et al., EPL 85, 67002 (2009)H. Ding et al., EPL 83, 47001 (2008)
![Page 11: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/11.jpg)
K. Seo, A. B. Bernevig, J. Hu PRL 101, 206404 (2008)
Order parameters in momentum Space
coskxcosky, s±-wave
Real space configuration of pairing symmetry
--
-
-
+++
local interactionsJ1- J2
pnictides: large J2 and FS topology favor
cuprates: large J1 and FS topology favor coskx–cosky)/2, d-wave
J1 – J2 model predicts almost isotropic s± gap
![Page 12: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/12.jpg)
I. MazinPRB 79, 060502 (2009)
D.H. Lee EPL 85, 37005 (2009)
S. GraserNJP 11, 025016 (2009)
when
Most weak-coupling theories predict anisotropic s± gap
![Page 13: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/13.jpg)
overdoped Ba0.3K0.7Fe2As2 (Tc ~ 20K)
K. Nakayama et al., PRB 83, 020501(R) (2011)
![Page 14: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/14.jpg)
underdoped Ba0.75K0.25Fe2As2 (Tc = 26K)
Y.-M. Xu et al., Nature Communications2, 392 (2011)
![Page 15: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/15.jpg)
Doping dependence of the SC gaps in Ba1-xKxFe2As2
K. Nakayama et al., PRB 83, 020501(R) (2011)
![Page 16: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/16.jpg)
Electron doped BaFe1.85Co0.15As2 (Tc = 25.5K)
K. Terashima et al, PNAS 106, 7330 (2009)
![Page 17: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/17.jpg)
kz dependence of SC gapssingle gap function
Y.-M. Xu et al., Nature Physics 7, 198 (2011)
Jab = 30Jc = 5
2/1
≈ Jc/Jab
≈ 0.17
![Page 18: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/18.jpg)
“111” - NaFe0.95Co0.05As (Tc = 18K)
Z.-H. Liu et al., arXiv:1008.3265, PRB
![Page 19: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/19.jpg)
“11” - FeTe0.55Se0.45 (Tc = 13K)
![Page 20: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/20.jpg)
J1 = -34J2 = 22J3 = 6.8
2/3
≈ J2/J3
≈ 0.3
H. Miao et al., arXiv:1107.0985
![Page 21: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/21.jpg)
(Tl,K)Fe2-xSe2 (Tc ~ 30K)
T. Qian et al., PRL (2011)
![Page 22: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/22.jpg)
Isotropic SC gap on electron FS
X.-P. Wang et al., EPL 93, 57001 (2011)J1 < 0, FM, d-wave is not favored
![Page 23: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/23.jpg)
Selection Rules of Pairing Symmetry
Overlap strength between pairing form factor and Fermi surface
OS =
Self-consistent meanfield equation for t-J model
![Page 24: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/24.jpg)
Three classes of high-Tc superconductors
J1 J2 J2+J3
![Page 25: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/25.jpg)
Three classes of high-Tc superconductors
J1 J2 J2+J3
![Page 26: ARPES studies of unconventional](https://reader036.vdocuments.mx/reader036/viewer/2022062504/5a4d1b817f8b9ab0599bb407/html5/thumbnails/26.jpg)
Summary
1.The SC gap of all iron-based superconductors measured by ARPES can by described approximately by J1-J2-J3 model
1.A possible unified paradigm of high-Tc
superconductivity: local AFM magnetic exchange + collaborative FS topology
J.-P. Hu and H. Ding, arXiv:1107.1334