共 50 条
- [1] Evidence of the two surface states of (Bi0.53Sb0.47)2Te3 films grown by van der Waals epitaxyScientific Reports, 3Liang He论文数: 0 引用数: 0 h-index: 0机构: University of California,Department of Electrical EngineeringXufeng Kou论文数: 0 引用数: 0 h-index: 0机构: University of California,Department of Electrical EngineeringMurong Lang论文数: 0 引用数: 0 h-index: 0机构: University of California,Department of Electrical EngineeringEun Sang Choi论文数: 0 引用数: 0 h-index: 0机构: University of California,Department of Electrical EngineeringYing Jiang论文数: 0 引用数: 0 h-index: 0机构: University of California,Department of Electrical EngineeringTianxiao Nie论文数: 0 引用数: 0 h-index: 0机构: University of California,Department of Electrical EngineeringWanjun Jiang论文数: 0 引用数: 0 h-index: 0机构: University of California,Department of Electrical EngineeringYabin Fan论文数: 0 引用数: 0 h-index: 0机构: University of California,Department of Electrical EngineeringYong Wang论文数: 0 引用数: 0 h-index: 0机构: University of California,Department of Electrical EngineeringFaxian Xiu论文数: 0 引用数: 0 h-index: 0机构: University of California,Department of Electrical EngineeringKang L. Wang论文数: 0 引用数: 0 h-index: 0机构: University of California,Department of Electrical Engineering
- [2] Observation of Quantum Hall effect in an ultra-thin (Bi0.53Sb0.47)2Te3 filmAPPLIED PHYSICS LETTERS, 2017, 110 (21)Zou, Wenqin论文数: 0 引用数: 0 h-index: 0机构: Nanjing Univ, Dept Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Jiangsu, Peoples R China Nanjing Univ, Dept Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Jiangsu, Peoples R ChinaWang, Wei论文数: 0 引用数: 0 h-index: 0机构: Nanjing Univ, Sch Elect Sci & Engn, York Nanjing Joint Ctr YNJC Spintron & Nano Engn, Nanjing 210093, Jiangsu, Peoples R China Nanjing Univ, Dept Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Jiangsu, Peoples R ChinaKou, Xufeng论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA Nanjing Univ, Dept Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Jiangsu, Peoples R ChinaLang, Murong论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA Nanjing Univ, Dept Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Jiangsu, Peoples R ChinaFan, Yabin论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA Nanjing Univ, Dept Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Jiangsu, Peoples R ChinaChoi, Eun Sang论文数: 0 引用数: 0 h-index: 0机构: Natl High Magnet Field Lab, Tallahassee, FL 32310 USA Nanjing Univ, Dept Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Jiangsu, Peoples R ChinaFedorov, Alexei V.论文数: 0 引用数: 0 h-index: 0机构: Lawrence Berkeley Natl Lab, Adv Light Source Div, 1 Cyclotron Rd, Berkeley, CA 94720 USA Nanjing Univ, Dept Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Jiangsu, Peoples R ChinaWang, Kejie论文数: 0 引用数: 0 h-index: 0机构: Nanjing Univ, Sch Elect Sci & Engn, York Nanjing Joint Ctr YNJC Spintron & Nano Engn, Nanjing 210093, Jiangsu, Peoples R China Nanjing Univ, Dept Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Jiangsu, Peoples R ChinaHe, Liang论文数: 0 引用数: 0 h-index: 0机构: Nanjing Univ, Sch Elect Sci & Engn, York Nanjing Joint Ctr YNJC Spintron & Nano Engn, Nanjing 210093, Jiangsu, Peoples R China Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA Nanjing Univ, Dept Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Jiangsu, Peoples R ChinaXu, Yongbing论文数: 0 引用数: 0 h-index: 0机构: Nanjing Univ, Sch Elect Sci & Engn, York Nanjing Joint Ctr YNJC Spintron & Nano Engn, Nanjing 210093, Jiangsu, Peoples R China Nanjing Univ, Dept Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Jiangsu, Peoples R ChinaWang, Kang. L.论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA Nanjing Univ, Dept Phys, Natl Lab Solid State Microstruct, Nanjing 210093, Jiangsu, Peoples R China
- [3] Revisiting the van der Waals Epitaxy in the Case of (Bi0.4Sb0.6)2Te3 Thin Films on Dissimilar SubstratesNANOMATERIALS, 2022, 12 (11)Mulder, Liesbeth论文数: 0 引用数: 0 h-index: 0机构: Univ Twente, MESA Inst Nanotechnol, NL-7500 AE Enschede, Netherlands Univ Twente, MESA Inst Nanotechnol, NL-7500 AE Enschede, NetherlandsWielens, Daan H.论文数: 0 引用数: 0 h-index: 0机构: Univ Twente, MESA Inst Nanotechnol, NL-7500 AE Enschede, Netherlands Univ Twente, MESA Inst Nanotechnol, NL-7500 AE Enschede, NetherlandsBirkholzer, Yorick A.论文数: 0 引用数: 0 h-index: 0机构: Univ Twente, MESA Inst Nanotechnol, NL-7500 AE Enschede, Netherlands Univ Twente, MESA Inst Nanotechnol, NL-7500 AE Enschede, Netherlands论文数: 引用数: h-index:机构:Concepcion, Omar论文数: 0 引用数: 0 h-index: 0机构: Univ Twente, MESA Inst Nanotechnol, NL-7500 AE Enschede, Netherlands Forschungszentrum Julich, Peter Grunberg Inst PGI 9, D-52425 Julich, Germany Univ Twente, MESA Inst Nanotechnol, NL-7500 AE Enschede, Netherlands
- [4] Surface-bulk coupling in a Bi2Te3 nanoplate grown by van der Waals epitaxyNANOSCALE, 2022, 14 (07) : 2586 - 2592Li, Xiaobo论文数: 0 引用数: 0 h-index: 0机构: Peking Univ, Beijing Key Lab Quantum Devices, Key Lab Phys & Chem Nanodevices, Beijing 100871, Peoples R China Peking Univ, Sch Elect, Beijing 100871, Peoples R China Peking Univ, Acad Adv Interdisciplinary Studies, Beijing 100871, Peoples R China Peking Univ, Beijing Key Lab Quantum Devices, Key Lab Phys & Chem Nanodevices, Beijing 100871, Peoples R ChinaMeng, Mengmeng论文数: 0 引用数: 0 h-index: 0机构: Peking Univ, Beijing Key Lab Quantum Devices, Key Lab Phys & Chem Nanodevices, Beijing 100871, Peoples R China Peking Univ, Sch Elect, Beijing 100871, Peoples R China Peking Univ, Beijing Key Lab Quantum Devices, Key Lab Phys & Chem Nanodevices, Beijing 100871, Peoples R ChinaHuang, Shaoyun论文数: 0 引用数: 0 h-index: 0机构: Peking Univ, Beijing Key Lab Quantum Devices, Key Lab Phys & Chem Nanodevices, Beijing 100871, Peoples R China Peking Univ, Sch Elect, Beijing 100871, Peoples R China Peking Univ, Beijing Key Lab Quantum Devices, Key Lab Phys & Chem Nanodevices, Beijing 100871, Peoples R ChinaTan, Congwei论文数: 0 引用数: 0 h-index: 0机构: Peking Univ, Coll Chem & Mol Engn, Ctr Nanochem, Beijing Natl Lab Mol Sci BNLMS, Beijing 100871, Peoples R China Peking Univ, Beijing Key Lab Quantum Devices, Key Lab Phys & Chem Nanodevices, Beijing 100871, Peoples R ChinaZhang, Congcong论文数: 0 引用数: 0 h-index: 0机构: Peking Univ, Coll Chem & Mol Engn, Ctr Nanochem, Beijing Natl Lab Mol Sci BNLMS, Beijing 100871, Peoples R China Peking Univ, Beijing Key Lab Quantum Devices, Key Lab Phys & Chem Nanodevices, Beijing 100871, Peoples R ChinaPeng, Hailin论文数: 0 引用数: 0 h-index: 0机构: Peking Univ, Coll Chem & Mol Engn, Ctr Nanochem, Beijing Natl Lab Mol Sci BNLMS, Beijing 100871, Peoples R China Peking Univ, Beijing Key Lab Quantum Devices, Key Lab Phys & Chem Nanodevices, Beijing 100871, Peoples R ChinaXu, H. Q.论文数: 0 引用数: 0 h-index: 0机构: Peking Univ, Beijing Key Lab Quantum Devices, Key Lab Phys & Chem Nanodevices, Beijing 100871, Peoples R China Peking Univ, Sch Elect, Beijing 100871, Peoples R China Beijing Acad Quantum Informat Sci, Beijing 100193, Peoples R China Peking Univ, Beijing Key Lab Quantum Devices, Key Lab Phys & Chem Nanodevices, Beijing 100871, Peoples R China
- [5] Research Update: Van-der-Waals epitaxy of layered chalcogenide Sb2Te3 thin films grown by pulsed laser depositionAPL MATERIALS, 2017, 5 (05):Hilmi, Isom论文数: 0 引用数: 0 h-index: 0机构: Leibniz Inst Oberflachenmodifizierung IOM, D-04318 Leipzig, Germany Leibniz Inst Oberflachenmodifizierung IOM, D-04318 Leipzig, GermanyLotnyk, Andriy论文数: 0 引用数: 0 h-index: 0机构: Leibniz Inst Oberflachenmodifizierung IOM, D-04318 Leipzig, Germany Leibniz Inst Oberflachenmodifizierung IOM, D-04318 Leipzig, GermanyGerlach, Juergen W.论文数: 0 引用数: 0 h-index: 0机构: Leibniz Inst Oberflachenmodifizierung IOM, D-04318 Leipzig, Germany Leibniz Inst Oberflachenmodifizierung IOM, D-04318 Leipzig, GermanySchumacher, Philipp论文数: 0 引用数: 0 h-index: 0机构: Leibniz Inst Oberflachenmodifizierung IOM, D-04318 Leipzig, Germany Leibniz Inst Oberflachenmodifizierung IOM, D-04318 Leipzig, GermanyRauschenbach, Bernd论文数: 0 引用数: 0 h-index: 0机构: Leibniz Inst Oberflachenmodifizierung IOM, D-04318 Leipzig, Germany Univ Leipzig, Felix Bloch Inst Festkorperphys, D-04103 Leipzig, Germany Leibniz Inst Oberflachenmodifizierung IOM, D-04318 Leipzig, Germany
- [6] Atomic scale structure and chemistry of Bi2Te3/GaAs interfaces grown by metallorganic van der Waals epitaxyAPPLIED PHYSICS LETTERS, 2013, 102 (08)Dycus, J. Houston论文数: 0 引用数: 0 h-index: 0机构: N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USAWhite, Ryan M.论文数: 0 引用数: 0 h-index: 0机构: N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USAPierce, Jonathan M.论文数: 0 引用数: 0 h-index: 0机构: RTI Int, Ctr Solid State Energet, Res Triangle Pk, NC 27709 USA N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USAVenkatasubramanian, Rama论文数: 0 引用数: 0 h-index: 0机构: RTI Int, Ctr Solid State Energet, Res Triangle Pk, NC 27709 USA N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USALeBeau, James M.论文数: 0 引用数: 0 h-index: 0机构: N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA
- [7] Electrical Detection of Spin-Polarized Surface States Conduction in (Bi0.5Sb0.47)2Te3 Topological InsulatorNANO LETTERS, 2014, 14 (09) : 5423 - 5429Tang, Jianshi论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USA Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USAChang, Li-Te论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USA Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USAKou, Xufeng论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USA Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USAMurata, Koichi论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USA Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USAChoi, Eun Sang论文数: 0 引用数: 0 h-index: 0机构: Natl High Magnet Field Lab, Tallahassee, FL 32310 USA Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USALang, Murong论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USA Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USAFan, Yabin论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USA Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USAJiang, Ying论文数: 0 引用数: 0 h-index: 0机构: Zhejiang Univ, Ctr Electron Microscopy, Hangzhou 310027, Peoples R China Zhejiang Univ, State Key Lab Silicon Mat, Dept Mat Sci & Engn, Hangzhou 310027, Peoples R China Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USAMontazeri, Mohammad论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USA Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USAJiang, Wanjun论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USA Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USAWang, Yong论文数: 0 引用数: 0 h-index: 0机构: Zhejiang Univ, Ctr Electron Microscopy, Hangzhou 310027, Peoples R China Zhejiang Univ, State Key Lab Silicon Mat, Dept Mat Sci & Engn, Hangzhou 310027, Peoples R China Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USAHe, Liang论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USA Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USAWang, Kang L.论文数: 0 引用数: 0 h-index: 0机构: Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USA Univ Calif Los Angeles, Device Res Lab, Dept Elect Engn, Los Angeles, CA 90095 USA
- [8] OXIDATION OF FILMS OF SOLID-SOLUTIONS (BI, SB)2TE3INORGANIC MATERIALS, 1979, 15 (01) : 26 - 29GELFGAT, DM论文数: 0 引用数: 0 h-index: 0DASHEVSKII, ZM论文数: 0 引用数: 0 h-index: 0KOLOMOETS, NV论文数: 0 引用数: 0 h-index: 0POTUPA, NP论文数: 0 引用数: 0 h-index: 0
- [9] Study of the Oxidation of Films of (Bi, Sb)2Te3 Solid Solutions.Izvestiya Akademii Nauk SSSR, Neorganicheskie Materialy, 1979, 15 (01): : 37 - 41Gel'frat, D.M.论文数: 0 引用数: 0 h-index: 0Dashevskii, Z.M.论文数: 0 引用数: 0 h-index: 0Kolomoets, N.V.论文数: 0 引用数: 0 h-index: 0Potupa, N.P.论文数: 0 引用数: 0 h-index: 0
- [10] Impurity states in the magnetic topological insulator V:(Bi,Sb)2Te3PHYSICAL REVIEW B, 2016, 94 (19)Peixoto, Thiago R. F.论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanyBentmann, Hendrik论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanySchreyeck, Steffen论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 3, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanyWinnerlein, Martin论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 3, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanySeibel, Christoph论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanyMaass, Henriette论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanyAl-Baidhani, Mohammed论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanyTreiber, Katharina论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanySchatz, Sonja论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanyGrauer, Stefan论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 3, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanyGould, Charles论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 3, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanyBrunner, Karl论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 3, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanyErnst, Arthur论文数: 0 引用数: 0 h-index: 0机构: Max Planck Inst Microstruct Phys, Weinberg 2, D-06120 Halle, Saale, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanyMolenkamp, Laurens W.论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 3, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, GermanyReinert, Friedrich论文数: 0 引用数: 0 h-index: 0机构: Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Rontgen Res Ctr Complex Mat RCCM, Fak Phys & Astron, D-97074 Wurzburg, Germany Univ Wurzburg, Expt Phys 7, Fak Phys & Astron, D-97074 Wurzburg, Germany