High-Resolution Photoelectron Momentum Microscopy of Organic Charge-Transfer Salts B8 Gerd Schönhense (Universität Mainz) Charge localization in (DOEO)4[HgBr]4•TCE Techniques Achievements: Temperature-dependent HAXPES crossing charge localization transition Correlation between anisotropy parameter, XPS and HAXPES energy shifts and line redistribution Goals and work program: Full experimental characterization of band structure in wide temperature range by momentum microscopy NEXAFS: Near-edge X-ray absorption fine structure EF Absorption/Electron yield N1s hv = 400 eV π* π*, σ* K-edge Near-edge fine structure (NEXAFS) Beamline: WERA, ANKA, Karlsruhe Energy range 100-1500 eV Base vacuum 10-11 mbar Sample temperature 20 - 400 K Energy resolution 100 meV B12 Chernenkaya et.al., SSP, accepted Koplak et.al., EPJB, submitted HAXPES Beamline: MAX II, Lund, Sweden Energy range 100-1500 eV Base vacuum 10-11 mbar Sample temperature 50 - 400 K Energy resolution 28 meV N → N* ∆ transport anisotropy parameter (R- R )/R O XPS energy shifts □ HAXPES peak intensities HAXPES: Hard X-ray photoelectron spectroscopy Beamline P09 Petra III, DESY Photon energy 5000 - 15000 eV Base vacuum 2 · 10-8 mbar Sample temperature is 20 - 800 K Energy resolution is 250 meV Electronic structure of κ-(BEDT-TTF)2Cu[N(CN)2]Br Achievements: Pilot experiments on temperature-dependent NEXAFS and room temperature k-microscopy hn=6 keV First results on -Br TiSa (2PPE) 2h =6.6 eV N → N - 1 Photoelectron momentum microscopy @ 300 K Bi2Te3 Goals and work program: Temperature dependent NEXAFS crossing the glasslike transition Band structure by momentum microscopy B2 Preliminary results Beamline U125-2 SGM, BESSY Photon energy 30-200 eV Base vacuum 10-10 mbar Sample temperature 100 - 300 K Energy resolution 60 meV, k-resolution 3.10-2 Å-1 Data acquisition time: seconds - minutes 3D image detector (delay-line type) Charge-transfer in thiophene-based thin films B10 DTBDT (HOMO ~ -5.42 eV) Achievements: Experiments on room temperature NEXAFS on thin films of DTBDT donor in composition with TCNQ and F4-TCNQ acceptor show electron density redistribution on TCNQ molecule IR analysis gives value of 0.22 eV for charge transfer in DTBDT-TCNQ system Goals and work program: NEXAFS on single crystals and comparison with thin films + F4-TCNQ +TCNQ (LUMO ~ - 5.25 eV) (LUMO ~ - 4.82 eV) Staffing of the project from auxiliary support Alisa Chernenkaya (Ph.D. student) - NEXAFS and HAXPES measurements on (BEDT-TTF)2X and (TMTTF)2X families - Momentum microscopy on κ-(BEDT-TTF)2Cu[N(CN)2]Br around the glasslike transition T = 77 K N.N. (Ph.D. student) Momentum microscopy on (TMTTF)2X family, κ-d8-(BEDT-TTF)2Cu[N(CN)2]Br, κ-(BEDT-TTF)2Cu[N(CN)2]Cl Investigation of inhomogeneity in TTF-CA thin films in the region of the neutral to ionic phase transition Crystal structure of DTBDT-TCNQ charge-transfer compound B4 Transregional Collaborative Research Centre SFB/TR 49 Frankfurt / Kaiserslautern / Mainz