Crossing the gap from p- to n-type doping: nature of the states near the chemical potential in La(2)-(x)Sr(x)CuO(4) and Nd(2-x)Ce(x)CuO(4-delta)

P G Steeneken; L H Tjeng; G A Sawatzky; A Tanaka; O Tjernberg; G Ghiringhelli; N B Brookes; A A Nugroho; A A Menovsky

doi:10.1103/PhysRevLett.90.247005

Crossing the gap from p- to n-type doping: nature of the states near the chemical potential in La(2)-(x)Sr(x)CuO(4) and Nd(2-x)Ce(x)CuO(4-delta)

Phys Rev Lett. 2003 Jun 20;90(24):247005. doi: 10.1103/PhysRevLett.90.247005. Epub 2003 Jun 19.

Authors

P G Steeneken¹, L H Tjeng, G A Sawatzky, A Tanaka, O Tjernberg, G Ghiringhelli, N B Brookes, A A Nugroho, A A Menovsky

Affiliation

¹ MSC, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.

PMID: 12857219
DOI: 10.1103/PhysRevLett.90.247005

Abstract

We report on an x-ray absorption and resonant photoemission study on single crystals of the high-T(c) cuprates La2-xSrxCuO4 and Nd(2-x)Ce(x)CuO(4-delta). Using an intrinsic energy reference, we find that the chemical potential of La2-xSrxCuO4 lies near the top of the La2CuO4 valence band whereas in Nd(2-x)Ce(x)CuO(4-delta) it is situated near the bottom of the Nd2CuO4 conduction band. The data clearly establish that the introduction of Ce in Nd2CuO4 results in electrons being doped into the CuO2 planes. We infer that the states closest to the chemical potential have a Cu 3d(10) singlet origin in Nd(2-x)Ce(x)CuO(4-delta) and a 3d(9)L singlet origin in La2-xSrxCuO4.