Density of states of hole-doped manganites: a scanning-tunneling-microscopy/spectroscopy study

Biswas, Amlan ; Elizabeth, Suja ; Raychaudhuri, A. K. ; Bhat, H. L. (1999) Density of states of hole-doped manganites: a scanning-tunneling-microscopy/spectroscopy study Physical Review B: Condensed Matter and Materials Physics, 59 (8). pp. 5368-5376. ISSN 1098-0121

PDF - Author Version

Official URL:

Related URL:


Variable temperature scanning-tunneling-microscopy/spectroscopy studies on single crystals and epitaxial thin films of hole-doped manganites, which show colossal magnetoresistance, have been done. We have investigated the variation of the density of states (DOS), at and near the Fermi energy (Ef), as a function of temperature. Simple calculations have been carried out, to find out the effect of temperature on the tunneling spectra and extract the variation of density of states with temperature, from the observed data. We also report here atomic resolution images, on the single crystals and larger range images showing the growth patterns on thin films. Our investigation shows unambiguously that there is a rapid variation in density of states for temperatures near the Curie temperature (Tc). While for temperatures below Tc, a finite DOS is observed at Ef, for temperatures near Tc a hard gap opens up in the density of states near Ef. For temperatures much higher than Tc, this gap most likely gives way to a soft gap. The observed hard gap for temperatures near Tc is somewhat higher than the transport gap for all the materials. For different materials, we find that the magnitude of the hard gap decreases as the Tc of the material increases and eventually, for materials with a Tc close to 400 K, the value of the gap approaches zero.

Item Type:Article
Source:Copyright of this article belongs to The American Physical Society.
ID Code:42688
Deposited On:06 Jun 2011 05:53
Last Modified:17 May 2016 23:54

Repository Staff Only: item control page