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Early transition metal oxides, particularly those of Ti and V, exhibit a wide range of interesting electronic and magnetic properties. Photoemission spectroscopy offers the unique possibility of mapping out the electronic structure of the occupied electron states in such systems. However, the extreme surface sensitivity of the technique ensures that only the surface and the near surface regions of any sample are probed. Our past results1-4 on Ca1-xSrxVO3 and La1-xCaxVO3 clearly established that the electronic structure of the surface region is drastically different from that of the bulk in such cases; we also provided a reliable method to separate the surface and the bulk contributions. This separation allowed us to deduce some very unusual behaviors of the electronic structures in these systems.
A number of recent studies5-7 on Ca1-xSrxVO3, however, has regenerated interest in this series of compounds with some unexpected and somewhat contradictory7 results. Presenting unpublished results, we address this recent puzzle concerning the electronic structure of these compounds.
This work is carried in collaboration with K. Maiti, U. Manju, P. Mahadevan, I.H. Inoue, and C. Carbone. References: 1. K. Maiti et al., Phys. Rev. Lett. 80, 2885 (1998). 2. K. Maiti et al., Phys. Rev. B 61, 2525 (2000). 3. K. Maiti et al., Europhys. Lett. 55, 246 (2001). 4. K. Maiti et al., Phys. Rev. B 70, 195112 (2004). 5. E. Pavarini et al., Phys. Rev. Lett. 92, 176403 (2004). 6. A. Liebsch, Phys. Rev. Lett. 90, 096401 (2003). 7. A. Sekiyama et al., Phys. Rev. Lett. 93, 156402 (2004) |