Observation of gapped quasiparticles in sodium charge-ordered Na1/2CoO2

✍ Scribed by Y. Xia; D. Qian; D. Hsieh; L. Wray; L. Viciu; R.J. Cava; M.Z. Hasan

• Book ID: 103885628
• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 251 KB
• Volume: 403
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2007.10.276

✦ Synopsis

Using high-resolution photoemission spectroscopy (ARPES), we present a systematic study of the insulating cobaltates. A singleparticle gap opening suggests that due to the material's unique topology an anisotropic particle-hole instability is present. Unlike conventional density waves, charge stripes or band insulators, the onset of the gap depends on the quasiparticle's quantum coherence which occurs well below the symmetry-breaking temperature of the crystal. Results are found to be in good agreement with bulk resistivity, specific heat and optical measurements.