X 21 SPring-8 XAFS 2016 (= )
X PC cluster Synchrotron TEM-EELS XAFS / EELS HΨ k = E k Ψ k
XANES/ELNES DFT ( + ) () WIEN2k, Elk, OLCAO () CASTEP, QUANTUM ESPRESSO FEFF, GNXAS, etc. Bethe-Salpeter (BSE) exciting, Elk, OCEAN, WIEN2k-BSE etc. (Configuration Interaction; CI) DFT-CI XANES/ELNES Typical element K-edge, L-edge [deep core] independent particle approximation Supercell + DFT + core-hole Multiple scattering theory K-edge, L-edge [shallow core (< 100eV)] two-particle theory strong excitonic effects Bethe-Salpeter Equation (BSE) Transition metal Rare-earth K-edge (main features) Supercell + DFT + core-hole Multiple scattering theory L 2,3 -edge, M 4,5 -edge, K-pre-edge many-electron theory multiplet effects Configuration Interaction (CI)
-e -e electron (r): electron cloud dr +Z 1 e +Z 2 e nucleus +Z 1 e +Z 2 e nucleus LDA, GGA dr t 2g e g t 2g e g
3d L 2,3 XANES/ELNES ( &3d) () -e +Z 1 e +Z 2 e E F, F E I, I
(CI) { i (r)} Configuration Interaction (CI) CI Coulomb
Ĥ = φ i ĥ φ j a i a j + 1 2 i,j φ i φ j ĝ φ k φ l a i a j a la k i,j,k,l φ i ĥ φ k = φ i (r)ĥ(r)φ j(r)dr φ i φ j ĝ φ k φ l = φ i (r 1)φ j (r 2)ĝ(r 1, r 2 )φ k (r 1 )φ l (r 2 )dr 1 dr 2 LDADirac SrTiO 3 unit cell TiO 6 8- + Ti Sr O
CI (3d) 0 (2p) 5 (3d) 1 (3d) 0 + (3d) 1 L (2p) 5 (3d) 1 + (2p) 5 (3d) 2 L Ikeno et al., J. Phys.: Condens. Matter 21, 104208 (2009). CI Ikeno et al., J. Phys.: Condens. Matter 21, 104208 (2009).
L 2,3 XANES Park et al., (2000) Gilbert et al., (2003) Rigan et al., (2001) XANES/ELNES X
L 2,3 XANES [2p 3d (4s) ] 3d LiNiO 2 Ni-L 2,3 ELNES NiO 2 () Ni 4+ low-spin LiNiO 2 Ni 3+ low-spin NiO Ni 2+ Theory: Ikeno et al., Phys. Rev. B 72, 075123 (2005). Experiments: Y. Koyama et al., J. Phys. Chem. B 109, 10749 (2005).
Li x MnO 3 Mn-L 2,3 XAS Kubobuchi, Ikeno, Mizoguchi, et al., Appl. Phys. Lett. 104, 053906 (2014). Li 2 MnO 3 Mn-K (1s4p) XAS [Yu et al., J. Electrochem. Soc. 156, A417 (2009).] DFT calc. [Koyama et al., J. Power Sources 189, 798 (2009).]
Li x MnO 3 Mn-L 2,3 XAS Kubobuchi, Ikeno, Mizuguchi, et al., Appl. Phys. Lett. 104, 053906 (2014). L 2,3 XANES +
ZnO:TM (TM=Mn,Ni) : ZnO-5mol%MnO 2, ZnO-1mol%NiO : Pulsed Laser Deposition (PLD) (Al 2 O 3 (0001)) GaN:Mn (Mn 8%) : NH 3 (MBE) (S. Sonoda et al., J. Cryst. Growth 237-239, 1358 (2002).) XANES (SPring-8 BL25SU, ALS BL8.0.1, KEK-PF BL11A) Mn-L 2,3 : 620-680eV Ni-L 2,3 : 835-890eV 0.1 ev e - slit monochromator sample synchrotron radiation slit mirror I 0 e - I ZnO:MnMn-L 2,3 XANES Theory Mn L 3 Mn 2+ in ZnO L 2 Theoretical fingerprinting Mn 3+ in ZnO
ZnO:MnMn-L 2,3 XANES Experiment Theory L 3 Zn 0.95 Mn 0.05 O () L 3 Mn 2+ in ZnO L 2 L 2 Mn 3+ in ZnO Mn+2Zn Mn ZnO:MnMn-L 2,3 XANES Experiment Theory L 3 Zn 0.95 Mn 0.05 O () L 3 Mn 2+ in ZnO () t 2 e L 2 L 2 Mn+2 Zn Mn Mn 2+ in ZnO () t 2 e
NiO, ZnO:NiNi-L 2,3 XANES Experiment Theory NiO () Ni 2+ in NiO (6) Zn 0.95 Ni 0.05 O () Ni 2+ in ZnO (4) Ni Ga 1-x Mn x NMn-L 2,3 XANES Experiment Theory Intensity (arb. units) L 3 Ga 1-x Mn x N x = 0.068 ferromagnetic L 2 Zn 1-x Mn x O x = 0.05 (Mn 2+ ) O 4 Intensity (arb. units) L 3 Mn 2+ in GaN (4) L 2 Mn 2+ in ZnO (4) 635 640 645 650 655 660 Photon energy (ev) 635 640 645 650 655 660 Energy (ev)
Ga 1-x Mn x N Mn-L 2,3 XANES Intensity (arb. units) Experiment Ga 1-x Mn x N x = 0.068 ferromagnetic Theory Mn 2+ in GaN Mn 3+ in GaN Intensity (arb. units) Experiment Ga 1-x Mn x N x = 0.068 ferromagnetic Mn 2+ : Mn 3+ = 85 : 15 635 640 645 650 655 660 Photon energy (ev) 635 640 645 650 655 660 Energy (ev) Mn 2+ /Mn 3+ (Mn 3+ ) X (XMCD) LCP RCP = +1 = -1 LCP - RCP
XMCD : J = 1 J = +1 (LCP) J = -1 (RCP) XMCD B : magnetic flux density B : Bohr magneton p : Slater determinant i : relativistic MO J ij
Theoretical Calculation of XMCD CI Zeeman Ĥ = Ĥ0 + ĤZeeman Ĥ Zeeman = μ B (l i +2s i ) B B B l i s i i : magnetic flux density : Bohr magneton : angular momentum : spin momentum NiFe 2 O 4 ()
NiFe 2 O 4 Ni-L 2,3 XMCD NiFe 2 O 4 Ni-L 2,3 XMCD XMCD x 5 (c) NFO Ni L 2,3 σ + 850 860 870 880 Photon Energy (ev) *M.C. Richter et al., Eur. Phys. J. Special Topics 169, 175 (2009). Ni+2B(6) σ
NiFe 2 O 4 Fe-L 2,3 XMCD NiFe 2 O 4 Fe-L 2,3 XMCD 705 XMCD x 10 (b) NFO Fe L 2,3 σ + σ 710 715 720 725 Photon Energy (ev) 730 *M.C. Richter et al., Eur. Phys. J. Special Topics 169, 175 (2009). Fe+3A,BA, BFe 3+
L 2,3 XANES/ELNES Dirac (CI)3d 3d L 2,3 XANES/ELNES / () XMCD