Tuning the dispersion of 4f bands in the heavy-fermion material YbRh₂Si₂

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• 作者：Denis V. Vyalikh ; Steffen Danzenbä ; cher ; Cornelius Krellner ; Kurt Kummer ; Christoph Geibel ; Yuri Kucherenko ; Clemens Laubschat ; Ming Shi ; Luc Patthey ; Rolf Follath ; Serguei L. Molodtsov
• 关键词：Heavy-fermion material ; f– ; d hybridization ; YbRh₂Si₂ ; ARPES
• 刊名：Journal of Electron Spectroscopy and Related Phenomena
• 出版年：2010
• 出版时间：July 2010
• 年：2010
• 卷：181
• 期：1
• 页码：70-75
• 全文大小：595 K

文摘

Localized Yb 4f and itinerant Rh 4d states are subject to substantial hybridization effects in the heavy-fermion material YbRh₂Si₂. The proximity to the Fermi level and the high anisotropy in k space naturally raise questions regarding the role of these hybridization effects for the observed, unusual physical properties. Using angle-resolved photoemission spectroscopy (ARPES) we found that the non-dispersive behavior of the localized Yb f states is broken around the Γ point due to interaction with approaching Rh 4d bands. The intriguing point here is that the hybridization strength turns out to be systematically tunable by electron doping of the material. Gradual deposition of silver atoms onto the atomically clean, silicon terminated surface of YbRh₂Si₂ leads to transfer of Ag 5s charge into the Rh 4d bands. This substantially changes the energy overlap, and thus the hybridization strength, between the interacting Yb 4f and Rh 4d bands in the surface and subsurface region. The shown possibility to control the variation of the f–d hybridization at the surface of heavy-fermion materials may also be helpful for other ARPES studies on the diverse phenomena in electron-correlated materials.