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Complete d-Band Dispersion and the Mobile Fermion Scale in NaxCoO2

D. Qian·L. Wray·D. Hsieh·L. Viciu·R. J. Cava·J. L. Luo·D. Wu·N. L. Wang·M. Z. Hasan
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Abstract

We utilize fine-tuned polarization selection coupled with excitation-energy variation of photoelectron signal to image the \textit{complete d}-band dispersion relation in sodium cobaltates. A hybridization gap anticrossing is observed along the Brillouin zone corner and the full quasiparticle band is found to emerge as a many-body entity lacking a pure orbital polarization. At low dopings, the quasiparticle bandwidth (Fermion scale, many-body \textit{E$_F$} $\sim$ 0.25 eV) is found to be smaller than most known oxide metals. The low-lying density of states is found to be in agreement with bulk-sensitive thermodynamic measurements for nonmagnetic dopings where the 2D Luttinger theorem is also observed to be satisfied.

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D. Qian, L. Wray, D. Hsieh, L. Viciu, R. J. Cava, J. L. Luo, D. Wu, N. L. Wang, M. Z. Hasan. 2006-11-24. Complete d-Band Dispersion and the Mobile Fermion Scale in NaxCoO2. https://doi.org/10.1103/physrevlett.97.186405

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