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14 results on '"C. Sohrt"'

1. Suppression of the Charge Density Wave State in Two-Dimensional 1T -TiSe2 by Atmospheric Oxidation

Author

Jinghui Wang, Liying Jiao, Lifei Sun, Kai Rossnagel, Qinghua Zhang, Chuanhui Chen, Chenggang Tao, Lin Gu, Guanchen Xu, Tianqi Zhao, C. Sohrt, and Dong Wang

Subjects
Superconductivity, Passivation, Chemistry, Nanotechnology, General Medicine, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Catalysis, 0104 chemical sciences, Metal, Chemical physics, visual_art, visual_art.visual_art_medium, Oxidation process, 0210 nano-technology, Charge density wave
Abstract

Two-dimensional (2D) metallic transition-metal dichalcogenides (TMDCs), such as 1T-TiSe2 , have recently emerged as unique platforms for exploring their exciting properties of superconductivity and the charge density wave (CDW). 2D 1T-TiSe2 undergoes rapid oxidation under ambient conditions, significantly affecting its CDW phase-transition behavior. We comprehensively investigate the oxidation process of 2D TiSe2 by tracking the evolution of the chemical composition and atomic structure with various microscopic and spectroscopic techniques and reveal its unique selenium-assisting oxidation mechanism. Our findings facilitate a better understanding of the chemistry of ultrathin TMDCs crystals, introduce an effective method to passivate their surfaces with capping layers, and thus open a way to further explore the functionality of these materials toward devices.

Published
2017

2. Does the excitation wavelength affect the ultrafast quenching dynamics of the charge-density wave in 1 T -TiSe 2 ?

Author

Lutz Kipp, Timm Rohwer, G. Rohde, C. Sohrt, Lexian Yang, Kai Rossnagel, K. Hanff, Michael Bauer, and A. Stange

Subjects
Radiation, Quenching (fluorescence), Chemistry, Charge density, Condensed Matter Physics, Electromagnetic radiation, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Wavelength, Secondary emission, Physical and Theoretical Chemistry, Atomic physics, Fermi gas, Charge density wave, Spectroscopy, Excitation
Abstract

The ultrafast spectral responses of a charge-ordered state in 1 T -TiSe 2 to the photo-excitation with laser-pulses of 790 nm and 395 nm center wavelength are compared. Time- and angle-resolved photoemission reveals pronounced differences in the energy-momentum distribution of the nascent electron gas; a distinct effect of the distribution character on the destruction dynamics of the charge-ordered state is, however, not observed.

Published
2014

3. Tracking the relaxation pathway of photo-excited electrons in 1T-TiSe2

Author

G. Rohde, Timm Rohwer, Lutz Kipp, K. Hanff, S. Hellmann, Kai Rossnagel, A. Stange, C. Sohrt, Michael Bauer, Adra Carr, Henry C. Kapteyn, Lexian Yang, and Margaret M. Murnane

Subjects
Materials science, Photoemission spectroscopy, Excited state, Femtosecond, General Physics and Astronomy, Relaxation (physics), General Materials Science, Position and momentum space, Physical and Theoretical Chemistry, Atomic physics, Absorption (electromagnetic radiation), Ultrashort pulse, Excitation
Abstract

The ultrafast dynamics of excited electrons in 1T-TiSe2 after absorption of a 390 nm light pulse is probed by time- and angle-resolved photoemission spectroscopy using femtosecond XUV pulses. It is demonstrated that the experimental approach can provide a comprehensive view of hot carrier motion in momentum space during relaxation back to equilibrium. This capability opens a new avenue in the investigation of energy dissipation processes in solids after intense optical excitation.

Published
2013

4. Hot electron cooling in graphite: Supercollision versus hot phonon decay

Author

L. X. Yang, Michael Bauer, A. Stange, C. Sohrt, K. Hanff, L.-P. Oloff, Kai Rossnagel, Petra Hein, G. Rohde, and K. Janssen

Subjects
Materials science, Condensed matter physics, Phonon, Graphite, Condensed Matter Physics, Hot electron, Electronic, Optical and Magnetic Materials
Published
2015

5. Oral and Poster Papers Submitted for Presentation at the 5th Congress of the EUGMS 'Geriatric Medicine in a Time of Generational Shift September 3–6, 2008 Copenhagen, Denmark

Author

M. T. Lonergan, B. Hovmand, M. Sánchez Cuervo, M. Tange Kristensen, C. Yau, Stefano Volpato, K. Christensen, K. Guha, J. Duggan, Y. Sawayama, J. F. M. de Jonghe, R. Rosenberg, K. Goupal, N. R. Jørgensen, P. Jordá, H. Kubšová, B. Riou, M. Monami, L. Özdemir, B. R. Duus, J. M. Fernandez Ibanez, Add Neuromed Study, S. Maertens, R. Winder, N. Akdemir, Carmelinda Ruggiero, F. Cambien, D. Bonnet, G. Barban, M. Fuentes, C. Datu, B. Ni Mhaille, D. G. Seymour, Toshio Hayashi, S. Lord, I. Kjeken, E. J. Schaefer, I. Raducanu, E. Tung, A. Truyols Bonet, D. Power, N. Morel, S. Edwards, C. Vigder, K. Promsopa, C. Geny, L. Derame, A. Dukat, A. Vilches-Moraga, K. Lihavainen, Z. Yang, R. M. Pircalabu, P. Huber, C. Eddy, A. Cella, C. Napoli, A. B. L. Pedersen, A. Fedeli, I. Sleiman, P. Weber, W. Kitisomprayoonkul, E. L. Marcus, K. Given, J. Sinclair-Cohen, S. O. Mahony, S. Vinkler, M. Krogseth, S. Otaguro, C. V. U. Øresund, D. Schoevaerdts, R. Pircalabu, B. Brack, H. Sasaki, F. Retornaz, I. Ionescu, M. Dubiel, J. Florian, L. Rokkedal, N. Quinlan, G. Dell’aquila, B. Way, C. Ionescu, T. Bermejo Vicedo, P. Eikelenboom, D. O’neill, T. Koga, A. Kachhia, M. R. Padilla Clemente, G. Batist, K. Moynier Vantieghem, P. Moerland, J. M. Bjordal, A. Pilotto, M. Michelet, R. Shafiei, Mirko Petrovic, J. Sulicka, J. Wagle, T. B. Wyller, J. Hrubanová, B. Stensrød, R. Ferretti, E. Turcu, S. Opris, A. Moreira, A. Zamora Mur, F J Martín Sánchez, N. Cogan, Marcello Maggio, Y. Kreslov, D. Ni Chroinin, G. Hanson, L. Kaiser, P. A. Kocaturk, S. Trainor, P. Takahashi, D. R. Collins, L. Campos, A. Björg Jönsdóttir, M. Cappuccio, V. Massart, T. Pattison, G. Notaridis, S. L. Ktvelä, S. Ghiorghe, Ruth Piers, L. Viati, M. Hollmann, Anja Velghe, Mikko P. Björkman, A. Zwinderman, K. Damkjær, P. Marsden, G. Cuneo, N. Bartoli, P. Gómez De Abia, A. Vilches Moraga, P. Campbell, Didem Sener Dede, B. Kirby, J. Oristrell, C. O’regan, T. Sander Pedersen, A. Hickey, R. Rozzini, B. Jansen, G. Fisher, N. Vogt-Ferrier, E. Kovari, B. Gasperini, K. Kalisvaart, N. Rye Jørgensen, K. Soda, U. Muster, K. Overgaard, J. Duiez-Domingo, M. Urbano, A. Oto, M. C. Cavallini, R. J. Van Marum, F. Gozukara, M. Cabrera Orozco, M. T. Olcoz-Chiva, A. Colvez, M. Di Bari, I. Cilesi, M. Migale, W. He, C. Dwyer, S. Engels, F. Hermmann, D. Small, Adam L. Gordon, Roberto Bernabei, R. Hnidei, C. Gonzalez-Rios, L. B. Husted, B. Dallapiccola, A. Moreau, R. Baron, U. Sveen, D. Chaiwanichsiri, A. Lopez Sierra, D. Villaneau, A. Mathur, G. Vedel Sørensen, P. Hemmi, F. Lattanzio, T. Frühwald, C. Marquis, A. Forest, B. Dalla Piccola, S. Lee, E. Ogawa, F. Coindreau, C. Rada, F. Lally, M. Yamada, K. Bakker, F. Comte, L. C. P. G. M. De Groot, H. L. Jørgensen, A. T. Isk, P. Schwarz, E. Portegijs, M. Kawakami, P. Giannakopoulos, A. Escolante Melich, M. O’ Connor, M. Rafanelli, P. Abete, M. Trabucchi, G. Clpaera, J. Vierendeels, M. Ramos, A. Salpakoski, G. Ziere, M. Ai, T. Fujisawa, K. I. Sørensen, C. Berard, K. Cobbaert, R. Fellin, M. Angel Mas, Phyo K. Myint, Burcu Balam Yavuz, K. Benmedjahed, P. Lampela, S. White, L. del Bianco, E. O. Ospedali Galliera, A. Frøland, L. Kozlov, M. T. Pacitti, P. Dave, B. Oeser, K. Kanaya, M. Rachita, Jean-Pierre Michel, Nadia Sourial, D. O’ Mahony, A. A. Piette, H. O’brien, K. Eiklid, A. J. Cruz-Jentoft, C. Shou, T. Bruun Wyller, J. Geerts, J. Korevaar, A. H. Johansen, P. Nimann Kannegaard, T. Korfitsen, A. Ayub, P. Baker, C. Scarcelli, A. Juszczak, L. S. Seest, A. Blundell, S. Bandinelli, P. A. F. Jansen, A. Maraviglia, E. S. Cankurtaran, B. Orhan, J. Vanakoski, K. J. Kalisvaart, M. Sakai, J. Oh, M. Henry, I. Kiviranta, S. Sanders, T. Mariani, A. H. Ranhoff, Mehmet Cankurtaran, B. Böhmdorfer, A. Tekeira, A. Lund, A. M. J. Maclullich, J. Hayashi, M. J. Lopez-Sanchez, S. M. I. Park, S. Willicombe, B. L. Langdahl, E. Lupeanu, A. Michael, R. Dias, G. Berrut, E. Ruffolo, D. Giet, Marianne Schroll, G. Onose, S. D. Shenkin, J. Driesen, T. Katsuya, C. Moe, M. San-Martin, Koenraad Vandewoude, A. Bambi, E. Shelley, C. Lamanna, B. Mc Eniry, B. Yoo, C. Colombi, H. Ekstrom, P. Gallagher, O. Mkhailova, A. Hnidei, F. P. Cariello, I. Moy, J. M. Vega Andion, G. Balci, F. Orso, W. Schrauwen, Patrizia Mecocci, J. L. Gallais, J. Saunders, M. Koefoed, J. Petrovicova, E. Paredes-Galan, C. Gutiérrez Fernández, Simon Lovestone, N. Berg, N. Weerasuriya, S. Biswas, K. Van Puyvelde, C. Chamot, T. Rantanenv, C. Rosen, K. O’connor, J. Ryg, L. Le Saint, D. A. Jones, M. Boncinelli, S. Baldasseroni, P. Barbisoni, E. Jones, C. F. Ambien, N. Dzerovych, P. Barry, A. Falanga, M. T. Olcoz Chiva, A. Skerris, S. Samandel, Antonio Cherubini, N. Binkley, A. Landi, P. Belli, G. Ditloto, M. Mellingsaeter, K. Wieczorowska-Tobis, L. Alonso Boix, C. Fernandez, V. Strelkova, G. Carmona, S. Amici, S. Mehrabian, J. Lietava, M. Iso-Aho, M. Masotti, I. G. Ftta, J. Carbonero Malberti, I. Carriere, A. Toornvliet, N. Grygoryeva, J. Soubeyrand, M. Cavalieri, Z. Malla, K. D. Pedersen, G. Clapera, J. M. Anton, N. R. Chopra, P. Eiken, S. Kapucu, G. Ventura, E. Cirinei, O. Vazquez, M. Checa, M. Filipa Seabra Pereira, R. Sylvest Mortensen, A. Osawa, J. Cunniffe, M. White, V. Batalha, A. Chatterjee, K. Bjøro, D. Zintchouk, E. Guillemard, R. Vreeswijk, C. Quinn, B. Romboli, G. Pepe, F. Simonsen, B. Morosanu, S. S. Celik, E. Kaykov, C. Bouras, B. Schousboe, N. van der Velde, P. Mowinckel, L. Toutous Trellu, J. Frimann, N. Vergis, T. Wulff, M. Salonoja, H. Doruk, A. Gonzalez, Dominique Benoit, L. Santos, Y. Ben-Israel, B. Grandal Leiros, F. Addante, C. Twomey, C. Sieber, C. Bonomini, P. Ziccardi, D. Carratelli, T. Jørgensen, F. Kasagi, A. Cebrian, M. Frisher, M. S. Brandt, W. Hussain, J. Mora, M. Alen, Maurits Vandewoude, C. Lidy, M. Burke, M. Mørch, A. Lyager, F. Huwez, J González Del Castillo, M. Cankuran, C. Prete, S. Anniss, S. Briggs, E. Bozoglu, S. Sipila, C. Fernandez Rios, H. Nomura, N. Faucher, L. Al-Dhahi, M. Gross, M. G. Longo, C. Schiaffini, H. Petersen, S. Crane, K. Brixen, C. Yucel, A. Leiro Manso, B. Yavuz, J. Petermans, W. Nielsen, T. Jokinen, C. L. Tofteng, D. Wan-Chow-Wah, B. Fantino, I. Barat, M. J. Lopez Sanchez, A. E. Larsen, E. Farrelly, S. Rostoft Kristjansson, J. M. Vega-Andion, V. Andrei, E. Pressel, B. Ni Bhuachalla, Steven Boonen, D. Simoni, M. G. Matera, E. Santillo, R. Sival, Dirk Vogelaers, Anna Skalska, S. Van Der Mark, H. Hirai, V. M. Chisciotti, R. Scoyni, M. Kallinen, A. Lopez-Sierra, E. Paredes Galan, D. Hagedorn, J. B. Lauritzen, Sölve Elmståhl, P. Mikes, M. Cohen, T. Vahlberg, L. E. Matzen, Gerda Verschraegen, H. Blain, E. Rees, R. Melton, T. L. J. Tammela, D. Aw, R. Miralles, E. Lopilato, M. van Zutphen, S. Ghorghe, N. Nissen, M. Lopponen, A. Oestergaard, A. Sorva, F. O’sullivan, M. Vanmeerbeek, A. Sclater, V. Juliebo, M.E. Fuentes Ferrer, S. Prada, E. Bryden, I. Maeve Rea, N. Furusyo, K. Cho, H. Cronin, F. Tigoulet, V. Povoroznyuk, F. Paris, P. Clarkson, P. E. Cotter, S. Rodriguez-Justo, F. Mazzella, E. de Waele, S. Trasciatti, O. Beauchet, E. Mannucci, K. N. Raun, C. Verdejo, S. Pautex, M. M. Mørch, P. Giniès, R. Garavan, J. Nobrega, S. Kinsella, L. Skippari, Howard Bergman, J. E. B. Jensen, T. Lee, P. Godart, B. Montero Errasquin, C. Nyhuus, Reijo S. Tilvis, G. Mancioli, D. Dawe, M. D’imperio, I. Miralles, J. Serra, M. Baglioni, C. Fallon, Y. Tatsukawa, J. Forristall, J. C. Leners, G. D’onofrio, J. de Backer, K. Flekkøy, L. Kyne, V. Dubois-Ferrière, C. Ryan, M. P. Sibret, A. Nesbakken, V. Ochiana, T. Iwamoto, E. Lotti, M. Marchionni, A. Clemmensen, J. Puustinen, S. Amor Andres, L. Wileman, Anette Hylen Ranhoff, S. Gillett, F. Lauretani, M. Gullo, H. Meluzínová, M. Seidahamd, P. de Antonio, A. Sgadari, E. Jespersen, A. Morelli, Palacios Huertas, C. Fraguglia, A. S. Rigaud, H. E. Andersen, B. Wizner, D. Fedak, J. Boddaert, Shaun T. O'Keeffe, D. O. ’Neill, B. Felli, C. Morales Ballesteros, S. Mcintosh, P. Such, O. Akyol, I. S. Young, J. M. Guralnik, A. Leiro-Manso, L. P. D’ambrosio, S. Rooij, G. Gold, H. Lee, C. Sohrt, A. Egan, D. Susanne Nielsen, C. Gravina, P. Rinaldi, C. Lestrup, S. F. Syed Farooq, M. Nuotio, L. Rexach Cano, C. Maraldi, F. Mangiaasche, Z. Mikes, E. M. Damsgaard, C. Di Serio, S. Pecchioni, S. Caplan, E. Gonzalez, M. Baccini, Y. Caine, J. Gladman, J. M. Ribera, B. Lundgren, V. Sharma, M. Morocutti, Sara Ercolani, B. H. C. Stricker, C. Popescu, M. Carpena-Ruiz, M. Verny, B. Hofman, A. Ungar, Y. Kumei, E. Topikova, L. Franceschi, S. Hussain, V. Serafini, K. Shipman, F. Sioulis, T. Coughlan, S. Bhat, B. Comert, K. Engedal, B. Kream, A. Iguchi, D. F. Vitale, M. Fornal, K. Kristiansen, I. Palma-Reis, E. Sixt, C. H. Foss, R. Rizzoli, M. Bartley, B. Fure, P. Freitas, C. Fernández Alonso, R. Njemini, F. Kelleher, A. Zamora Catevilla, S. Hoeck, F. Rashidi, J.M. Ribera Casado, M. Honing, A. Rajska-Neumann, B. D. Pedersen, A. Martins, C. M. J. Van Der Linden, D. Sharpe, R. Grue, Denis O'Mahony, J. Van der Heyden, J. Cristoffersen, Marianna Noale, U. Sommeregger, V. Goffredo, A. Qvist, Y. Akkuþ, M. T. E. Puts, M. Luque, M. P. De Antonio García, T. Takagi, N. Carroll, A. Salakowski, M. Belladonna, A. Hylen Ranhoff, S. Otokozawa, C. Ekdahl, E. Delgado Silveira, Stijn Blot, H. Mcgee, U. Senin, G. C. Parisi, S. Pedersen, F. Rengo, A. Renom, E. Vestbo, Y. Akkus, G. Van Hal, S. Murphy, V. Ducasse, G. Ryzhak, M. I. Arranz Peña, W. Knol, V. Lesauskaite, F. Patacchini, S. Abe, M. Narro-Vidal, C. Lund, N. Hayashi, M. van Breemen, H. Ohnishi, M. Torrente-Carballido, B. Bogen, H. Kayihan, Z. Tuna, C. Verdejo-Bravo, B. Battacharya, F. M. Borgbjerg, Kudret Aytemir, A. C. Drenth-Van Maanen, F. Gori, O. Duems, T.J.M. van der Cammen, Servet Ariogul, P. Villarroel, M. Kat, N. Petitpierre, I. Akyar, M. Franceschi, M. Ohishi, S. Cassano, Roy L. Soiza, T. Patel, A. M. Herghelegiu, M. Clarfield, S. Ballentyne, L. Lambertucci, Cm. Pena, A. Bayer, A. Salam, E. Moriarty, C. Roux, Y. Takasugi, M. García, C. Rodriguez-Pascual, P. Mikus, Y. Akyar, M. Torrente Carballido, V. Vayda, F. Rønholt, M. Khayat, K. Ina, O. Hazer, M. Falconer, H. N. Jacobsen, R. Custureri, H. Kasem, T. Bandholm, A. Allue Bergua, M. Levi, R. Rehman, M. Monette, C. Verdejo Bravo, O. Millot, N. Caffrey, Y. Kano, C. Cherubini, J. Kolesar, S. Maeshima, J. Fox, P. Aarnio, E. Henderson, J. Monette, M. MacMahon, L. Rytter, J. Nurminen, A. Abbas, A. S. Whitehead, G. Longobardi, Zekeriya Ulger, M. Hamada, A. Sofia Duque, Luigi Ferrucci, P. Lavikainen, J. Kennedy, I. Saez, E. Hegarty, Stefania Maggi, J. Touchon, A. Chandra, A. Bhangu, M. Labib, A. Rnould, A. Bojan, S. Mukherjee, N. Ferrara, F. Raschilas, G. Popescu, C. Annweiler, D. Hevey, D. Seripa, C. Danneels, I. Crome, M. Karlsson, Y. Kamiya, C. Carvell, I. Trani, T. van der Ploeg, G. Zulian, J. Bencke, V. Curran, P. Gherasim, B. Sejtved, R. Meade, Rose Anne Kenny, V. Curiale, A. Yu-Ballard, E. Azevedo, A. Leiros, P. Gil Gregorio, J. Gonzalez Armengol, H. Rakugi, M. C. Esculier, O. Poire, R. Raz, R. Gugliotta, M. Carpena Ruiz, Tony Mets, Ivan Bautmans, T. Karasevskaya, P. Eoin Cotter, T. Masud, C. Jeandel, K. Leckie, J. P. Lopes, R. Isoaho, A. E. Evans, F. Lacoin, C. Cho, B. Vincent, M. Lazaro, R. Cecchetti, M. Carpena, A. Kavanagh, S. Juhl Pedersen, Niccolò Marchionni, C. Swine, François Herrmann, G. O. Kavas, F. J. Garcia Garcia, S. Quintela, G. I. Prada, C. Hertogh, S. Sun Kapucu, P. Granberg, S. Byrne, R. Mcdermott, R. Van Der Stichele, A. M. Mello, A. Waldir Bezerra, J. de Jonghe, L. F. Moreno Ramiez, A. de Tena Fontaneda, M. H. Saldanha, H. Kehlet, G. V. Sørensen, M. Jylhä, J. Silvestre, K. Czabanowska, L. Gowran, F. Albertí Homar, M. de Saint-Hubert, R. Huupponen, P. le Lous, T. Bertsch, P. Dieppe, R. Topor-Madry, R. Van Gara, W. Bemelmans, V. Polcarová, C. Donnellan, B. Jørgensen, G. Leandro, S. L. Kivela, C. Boubakri, Sirpa Hartikainen, K. Ferguson, Z. Barrou, E. Costanzi, H. Hilleret, L. Danbaek, A. O’hanlon, C. Hürny, O. G. Olaru, V. Seux, C. Divoy, M. Mowe, E. Holm, H. J. Heppner, J. Martin, M. Isik, B. Gryglewska, A. Lilja, E. Romero, I. Pillay, V. Kijowska, M. Therese Lonergan, A. Alfaro Acha, M. Uyanik, A. Gabelle, P. Bueso, S. Sinha, M. Corritore, T. Shingo, E. Lacey, L. Cascavilla, R. Sulkava, K. Terumalai, S. Pellerito, Gaetano Crepaldi, R. Moe-Nilssen, Francesco Cacciatore, J. Breda, J. M. Del Rey, J. Teixeira, N. B. Nielsen, E. Granot, D. Speijer, S. A. Anstey, G. Masotti, I. G. Fita, S. Krajèík, P. Brynningsen, S. Maeda, N. Vanden Noortgate, J. Wiersinga, M. Teixeira Veríssimo, J. Cooke, N. Van Den Noortgate, K. Daly, M. M. Bisschop, A. Galmés Truyols, W.A. van Gool, J. Fernandez Soria, C. Sánchez Castellano, A. M. Cervera, E. Mossello, T. Lindhardt, C. Boulanger, E. Oziol, C. Hendriksen, A. M. Pazienza, L. Farner, P. Bastiani, F. Horgan, A. Deniz, P. Ammann, H. Takeoka, J. Lauritsen, L. Sandvik, S. S. Kapucu, I. Nakagawa, A. Jung, L. Brewer, Anne-Marie Schott, S. Zanieri, A. Teixeira, G. Parisi, P. Lund Nielsen, J. Holckova, P. Alcalde, B. Whelan, K. Toyoda, B. Dieudonne, G. Guerra, Meltem Halil, E. Garcia-Villar, R. Paz Maya, C. E. Mogensen, M. O’connor, A. Bonnerup Vind, L. Vich Martorell, F. Tarantini, Katarzyna Szczerbińska, I. Ozerov, R. Turk, M. Kamigaki, E. Mirewska, H. Bayes, S. Arino, P. Lyngholm-Kxærby, B.C. van Munster, F. Konishi, A. Morrione, C. Pena, P. Harbig, D. Gradinaru, F. Kee, B. Knold, L. Aiello, T. de Man, Renaat Peleman, Taina Rantanen, P. Birschel, P. Crome, R. Meyling, V. Khavinson, D. H. Kim, T. Luukkaala, Q. Garcia, K. Elkholy, D. Gillain, M. L. Seux, S. Greffard, P. Kjear, S. Sihvonen, Patricia M. Kearney, Tomasz Grodzicki, F. Favier, Dominique Vandijck, E. Palummeri, F. Caldi, Y. Parel, E. Jorge, L. O’connor, S. Dahlin Ivanoff, L. Tiret, K. Adie, G. Lucchetti, M. Lauridsen, A. C. Berggren, M. Simon, D. Adane, P. O. Lang, and V. Niro

Subjects
Gerontology, Geriatrics, 0303 health sciences, medicine.medical_specialty, Nutrition and Dietetics, 030309 nutrition & dietetics, Geriatrics gerontology, business.industry, media_common.quotation_subject, Alternative medicine, Medicine (miscellaneous), 03 medical and health sciences, Presentation, 0302 clinical medicine, medicine, 030212 general & internal medicine, Geriatrics and Gerontology, business, Quality of Life Research, media_common
Published
2008

6. How fast can a Peierls-Mott insulator be melted?

Author

Kai Rossnagel, Michael Bauer, A. Stange, and C. Sohrt

Subjects
Vibration, Materials science, Amplitude, Condensed matter physics, Photoemission spectroscopy, Mott insulator, Extreme ultraviolet, Crossover, Condensed Matter::Strongly Correlated Electrons, Insulator (electricity), Electronic structure, Physical and Theoretical Chemistry
Abstract

Time- and angle-resolved extreme ultraviolet photoemission spectroscopy is used to directly determine the momentum-dependent electronic structure dynamics in the layered Peierls-Mott insulators 1T-TaS(2) and 1T-TaSe(2) on the sub-300 fs time scale. Extracted spectroscopic order parameters display a global two-time-scale dynamics indicating a quasi-instantaneous loss of the electronic orders and a subsequent coherent suppression of the lattice distortion on a time scale related to the frequency of the charge-density-wave amplitude mode. After one half-cycle of coherent amplitude-mode vibration, a crossover state between insulator and metal with partially filled-in and partially closed Mott and Peierls gaps is reached. The results are discussed within the wider context of electronic order quenching in complex materials.

Published
2014

7. Ultrafast Modulation of the Chemical Potential inBaFe2As2by Coherent Phonons

Author

Ilya Eremin, C. Sohrt, Timm Rohwer, Laurenz Rettig, F. Chen, Margaret M. Murnane, Uwe Bovensiepen, Kai Rossnagel, K. Hanff, A. Stange, Tenio Popmintchev, Donglai Feng, R. Cortés, T. Wolf, J. Fink, Michael Bauer, Lexian Yang, Henry C. Kapteyn, G. Rohde, Lutz Kipp, and B. Kamble

Subjects
Physics, Condensed matter physics, Phonon, Photoemission spectroscopy, Fermi level, General Physics and Astronomy, Electron, Electronic structure, Coupling (probability), symbols.namesake, symbols, Sensitivity (control systems), Atomic physics, Electronic band structure
Abstract

Time- and angle-resolved extreme ultraviolet photoemission spectroscopy is used to study the electronic structure dynamics in ${\mathrm{BaFe}}_{2}{\mathrm{As}}_{2}$ around the high-symmetry points $\mathrm{\ensuremath{\Gamma}}$ and $M$. A global oscillation of the Fermi level at the frequency of the ${A}_{1g}(\mathrm{As})$ phonon mode is observed. It is argued that this behavior reflects a modulation of the effective chemical potential in the photoexcited surface region that arises from the high sensitivity of the band structure near the Fermi level to the ${A}_{1g}(\mathrm{As})$ phonon mode combined with a low electron diffusivity perpendicular to the layers. The results establish a novel way to tune the electronic properties of iron pnictides: coherent control of the effective chemical potential. The results further suggest that the equilibration time for the effective chemical potential needs to be considered in the ultrafast electronic structure dynamics of materials with weak interlayer coupling.

Published
2014

8. Time-domain classification of charge-density-wave insulators

Author

M. Kalläne, Henry C. Kapteyn, A. Stange, Kai Rossnagel, Michael Bauer, Timm Rohwer, Adra Carr, S. Hellmann, K. Hanff, C. Sohrt, Margaret M. Murnane, and Lutz Kipp

Subjects
Condensed Matter::Quantum Gases, Physics, Multidisciplinary, Condensed matter physics, Photoemission spectroscopy, General Physics and Astronomy, Insulator (electricity), General Chemistry, General Biochemistry, Genetics and Molecular Biology, Condensed Matter::Strongly Correlated Electrons, Time domain, Charge density wave, Temporal discrimination, Ultrashort pulse
Abstract

Distinguishing insulators by the dominant type of interaction is a central problem in condensed matter physics. Basic models include the Bloch-Wilson and the Peierls insulator due to electron-lattice interactions, the Mott and the excitonic insulator caused by electron-electron interactions, and the Anderson insulator arising from electron-impurity interactions. In real materials, however, all the interactions are simultaneously present so that classification is often not straightforward. Here, we show that time- and angle-resolved photoemission spectroscopy can directly measure the melting times of electronic order parameters and thus identify-via systematic temporal discrimination of elementary electronic and structural processes-the dominant interaction. Specifically, we resolve the debates about the nature of two peculiar charge-density-wave states in the family of transition-metal dichalcogenides, and show that Rb intercalated 1T-TaS(2) is a Peierls insulator and that the ultrafast response of 1T-TiSe(2) is highly suggestive of an excitonic insulator.

Published
2012

9. Gaps and kinks in the electronic structure of the superconductor2H-NbSe2from angle-resolved photoemission at 1 K

Author

D. J. Rahn, M. Kalläne, C. Sohrt, Kai Rossnagel, Timur K. Kim, S. Hellmann, and Lutz Kipp

Subjects
Brillouin zone, Superconductivity, Materials science, Condensed matter physics, Coupling parameter, Photoemission spectroscopy, Band gap, Condensed Matter::Superconductivity, Spectral gap, Electronic structure, Condensed Matter Physics, Anisotropy, Electronic, Optical and Magnetic Materials
Abstract

Angle-resolved photoemission spectroscopy at a temperature of 1 K is used to determine the wave-vector dependence of the spectral gap and band renormalization due to electron-phonon coupling in the layered chargedensity-wave superconductor 2H -NbSe2. The measured gap size and coupling parameter are Fermi-surface-sheet dependent and anisotropic. The largest energy gap, highest coupling strength, and strongest variation in both quantities are found on the double-walled Nb 4d-derived Fermi-surface sheet that is centered on the corners of the hexagonal Brillouin zone. On this sheet, the spectral gap has two distinct anticorrelated components associated with superconductivity and the charge-density wave. The results establish 2H -NbSe2 as a moderately correlated intermediate-coupling anisotropic multigap superconductor.

Published
2012

10. Time-Resolved X-Ray Photoelectron Spectroscopy at FLASH

Author

Alexander Föhlisch, F. Sorgenfrei, M. Marczynski-Bühlow, Harald Redlin, Michael Bauer, Wilfried Wurth, C. Sohrt, Martin Beye, Kai Rossnagel, Timm Rohwer, Franz Hennies, S. Hellmann, M. Kalläne, and Lutz Kipp

Subjects
Physics, General Physics and Astronomy, Physics::Optics, Nanosecond, Laser, Space charge, Electron spectroscopy, law.invention, Optical pumping, X-ray photoelectron spectroscopy, law, ddc:540, Atomic physics, Spectroscopy, Excitation
Abstract

The technique of time-resolved pump-probe x-ray photoelectron spectroscopy using the free-electron laser in Hamburg (FLASH) is described in detail. Particular foci lie on the macrobunch resolving detection scheme, the role of vacuum space-charge effects and the synchronization of pump and probe lasers. In an exemplary case study, the complete Ta 4f core-level dynamics in the layered charge-density-wave (CDW) compound 1T-TaS2 in response to impulsive optical excitation is measured on the sub-picosecond to nanosecond timescale. The observed multi-component dynamics is related to the intrinsic melting and reformation of the CDW as well as to extrinsic pump-laser-induced vacuum space-charge effects.

Published
2012

11. Ultrafast Melting of a Charge-Density Wave in the Mott Insulator1T−TaS2

Author

Timm Rohwer, Lutz Kipp, Harald Redlin, Alexander Föhlisch, S. Hellmann, F. Sorgenfrei, M. Kalläne, M. Marczynski-Bühlow, Kai Rossnagel, Wilfried Wurth, Franz Hennies, Michael Bauer, C. Sohrt, and Martin Beye

Subjects
Photoexcitation, Phase transition, Materials science, Condensed matter physics, Photoemission spectroscopy, Mott insulator, Femtosecond, General Physics and Astronomy, Atomic physics, Metal–insulator transition, Charge density wave, Mott transition
Abstract

Femtosecond time-resolved core-level photoemission spectroscopy with a free-electron laser is used to measure the atomic-site specific charge-order dynamics of the charge-density wave in the Mott insulator 1T-TaS2. After strong photoexcitation, a prompt loss of charge order and subsequent fast equilibration dynamics of the electron-lattice system are observed. On the time scale of electron-phonon thermalization, about 1 ps, the system is driven across a phase transition from a long-range charge ordered state to a quasiequilibrium state with domainlike short-range charge and lattice order. The experiment opens the way to study the nonequilibrium dynamics of condensed matter systems with full elemental, chemical, and atomic-site selectivity.

Published
2010

12. Collapse of long-range charge order tracked by time-resolved photoemission at high momenta

Author

M. Kalläne, S. Hellmann, A. Stange, Bartosz Slomski, Yanwei Liu, Lutz Kipp, Timm Rohwer, Kai Rossnagel, C. Sohrt, Luis Miaja Avila, Adra Carr, Stefan Mathias, Michael Bauer, and M. Wiesenmayer

Subjects
Multidisciplinary, Photon, Condensed matter physics, Chemistry, Photoemission spectroscopy, Inverse photoemission spectroscopy, Angle-resolved photoemission spectroscopy, Position and momentum space, 02 engineering and technology, Electronic structure, 021001 nanoscience & nanotechnology, 01 natural sciences, Topological insulator, 0103 physical sciences, Atomic physics, 010306 general physics, 0210 nano-technology, Electronic band structure
Abstract

Angle-resolved photoelectron spectroscopy (ARPES) is widely used to study the electronic structure of crystalline solids such as high-temperature superconductors, topological insulators and graphene-based materials. Time-resolved ARPES has opened the door to the study of the response of such electronic features on ultrafast timescales. Now Rohwer et al. add a new dimension. Using high photon energies, they are able to study ultrafast dynamics at high momenta, at which some of the most interesting fundamental phenomena occur. Applying the technique to the charge density wave material 1T-TiSe2, they obtain stroboscopic images of the electronic band structure at high momentum and show that atomic-scale periodic long-scale order collapses on a surprisingly short timescale of 20 femtoseconds. This work reveals rapid response times in photoinduced properties that could stimulate research into new types of ultrafast switching device. Angle-resolved photoemission spectroscopy (ARPES) is widely used to study the electronic structure of a wide range of correlated materials. Time-resolved ARPES allows the study of the response of such electronic features on ultrafast timescales; this paper now adds an exciting new dimension by using high photon energies that allow the study of ultrafast dynamics at high momenta, where often the most interesting fundamental phenomena occur. The technique is applied to the charge density wave material 1T-TiSe2 and it is shown with stroboscopic imaging of the electronic band structure at high momentum that atomic-scale periodic long-range order collapses on a surprisingly short timescale of 20 femtoseconds. Intense femtosecond (10−15 s) light pulses can be used to transform electronic, magnetic and structural order in condensed-matter systems on timescales of electronic and atomic motion1,2,3. This technique is particularly useful in the study4,5 and in the control6 of materials whose physical properties are governed by the interactions between multiple degrees of freedom. Time- and angle-resolved photoemission spectroscopy is in this context a direct and comprehensive, energy- and momentum-selective probe of the ultrafast processes that couple to the electronic degrees of freedom7,8,9,10. Previously, the capability of such studies to access electron momentum space away from zero momentum was, however, restricted owing to limitations of the available probing photon energy10,11. Here, using femtosecond extreme-ultraviolet pulses delivered by a high-harmonic-generation source, we use time- and angle-resolved photoemission spectroscopy to measure the photoinduced vaporization of a charge-ordered state in the potential excitonic insulator 1T-TiSe2 (refs 12, 13). By way of stroboscopic imaging of electronic band dispersions at large momentum, in the vicinity of the edge of the first Brillouin zone, we reveal that the collapse of atomic-scale periodic long-range order happens on a timescale as short as 20 femtoseconds. The surprisingly fast response of the system is assigned to screening by the transient generation of free charge carriers. Similar screening scenarios are likely to be relevant in other photoinduced solid-state transitions and may generally determine the response times. Moreover, as electron states with large momenta govern fundamental electronic properties in condensed matter systems14, we anticipate that the experimental advance represented by the present study will be useful to study the ultrafast dynamics and microscopic mechanisms of electronic phenomena in a wide range of materials.

Published
2010

13. CDW-superlattice suppression probed in time-resolved XUV-photoemission at the border of the Brillouin zone

Author

Timm Rohwer, Bartosz Slomski, A. Stange, Michael Bauer, Kai Rossnagel, M. Wiesenmayer, S. Hellmann, C. Sohrt, and Lutz Kipp

Subjects
Physics, Condensed matter physics, business.industry, Superlattice, Phase (waves), Brillouin zone, Optics, Condensed Matter::Superconductivity, Extreme ultraviolet, Condensed Matter::Strongly Correlated Electrons, Transient (oscillation), Time-resolved spectroscopy, business, Ultrashort pulse, Charge density wave
Abstract

Time- and angle-resolved XUV-photoemission at the border of the first Brillouin zone is employed to monitor the ultrafast suppression of a (2×2×2) reconstruction characteristic for the charge density wave (CDW) phase in 1T-TiSe2. The correlation of lattice dynamics and transient electronic response, which is probed in this experiment in parallel, provides new insights into the puzzling nature of the CDW mechanism in 1T-TiSe2.

Published
2010

14. A direct view onto the carrier dynamics in graphite at the H point

Author

Michael Bauer, Kai Rossnagel, Timm Rohwer, A. Stange, Lutz Kipp, C. Sohrt, S. Hellmann, and G. Rohde

Subjects
Physics, QC1-999, Nanotechnology, Electrolyte, Electron, Condensed Matter::Materials Science, Adsorption, Chemical physics, Excited state, Ultrafast laser spectroscopy, Graphite, Physics::Chemical Physics, Porosity, Spectroscopy
Abstract

The photophysics of charge transfer between the electron donating, surface adsorbed D149 dye and an electron accepting porous ZnO film was investigated by measuring excited state lifetimes using ultrafast transient absorption spectroscopy. We systematically varioed the production scheme of the sample including the electrolyte.

Published
2013

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