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Impact of Temperature on Seebeck Coefficient of Nodal Line Semimetal in Molecular Conductor
Version 1
: Received: 6 June 2024 / Approved: 10 June 2024 / Online: 10 June 2024 (09:28:10 CEST)
A peer-reviewed article of this Preprint also exists.
Suzumura, Y. Impact of Temperature on Seebeck Coefficient of Nodal Line Semimetal in Molecular Conductor. Crystals 2024, 14, 601. Suzumura, Y. Impact of Temperature on Seebeck Coefficient of Nodal Line Semimetal in Molecular Conductor. Crystals 2024, 14, 601.
Abstract
We examine the impact of temperature (T) on the Seebeck coefficient S, i.e., the T dependence of S for the single-component molecular conductor Pd(dddt)_2] (dddt = 5,6-dihydro-1,4-dithiin-2,3-dithiolate) with a half-filled band, where the coefficient is obtained from a ratio of the thermal conductivity to the electrical conductivity. The conductor exhibits Dirac electrons with a nodal line, which shows the energy variation around the chemical potential and the density of states (DOS) with a minimum. Using a three-dimensional tight-binding (TB) model in the presence of both impurity and electron--phonon (e--p) scatterings, we study the Seebeck coefficient S_y for the molecular stacking and the most conducting direction. The impact of T on S_y exhibits a sign change, where S_y > 0 with a maximum at high temperatures and S_y < 0 with a minimum at low temperatures. The T dependence of S_y suggests that the contribution from the conduction (valence) band is dominant at low (high) temperatures.The result is examined using a spectral conductivity \sigma_y(\epsilon,T) as a function of the energy $\epsilon$ close to the chemical potential \mu. Further, the Seebeck coefficients for perpendicular directions (x and z) are examined, to show both S_x and S_z being positive and no sign change in contrast to S_y.
Keywords
Seebeck coefficient; nodal line semimetal; single-component molecular conductor; spectral conductivity; DOS; tight-binding model
Subject
Physical Sciences, Condensed Matter Physics
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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