Year: 2011
Type: article
Abstract: For the thermoelectric properties of Na${}_{x}$CoO${}_{2}$, we analyze the effect of local Coulomb interaction and (disordered) potential differences for Co sites with adjacent Na ion or vacancy. The disorder potential alone increases the resistivity and reduces the thermopower, while the Coulomb interaction alone leads only to minor changes compared to the one-particle picture of the local-density approximation. Only combined, these two terms give rise to a substantial increase of the thermopower: the number of (quasi)electrons around the Fermi level is much more suppressed than that of the (quasi) holes. Hence there is a particle-hole imbalance acting in the same direction as a similar imbalance for the group velocities. Together, this interplay results in a large positive thermopower. Introducing a thermoelectric spectral density, we located the energies and momenta regions most relevant for the thermopower and changes thereof.
Source: Physical Review B
Authors: P. Wissgott, A. Toschi, G. Sangiovanni, K. Held
Institution: TU Wien
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1982954430