Behavior of the thermopower in amorphous materials at the metal-insulator transition

Villagonzalo, Cristine; Römer, Rudolf A.; Schreiber, Michael; MacKinnon, A.

doi:10.1103/physrevb.62.16446

Cited by 8 publications

(11 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…But we found [7] z = 1/ν ≪ 3. In addition, values of S(T ) [8,9] are at least an order of magnitude larger than in measurements of doped semiconductors [10] and amorphous alloys [11,12].In what follows, we show that we obtain the right order of magnitude [13] and good scaling for these thermoelectric transport properties by using a "modified" critical behavior of σ in the linear-response formulation for the Anderson model based on experimental data. …”

mentioning

confidence: 82%

“…(3) is merely due to the broadening of f and the T dependence of µ. The latter stems from the structure of the density of states, variations in which yield only negligible changes in L ij [13]. Thus, in order to model a correct T dependence of the L ij and, consequently, the transport properties, we need to reconsider what A(E) should be.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…In what follows, we show that we obtain the right order of magnitude [13] and good scaling for these thermoelectric transport properties by using a "modified" critical behavior of σ in the linear-response formulation for the Anderson model based on experimental data. In the linear-response formulation, the thermoelectric transport properties can be determined from the kinetic coefficients L ij [9], i.e.,…”

mentioning

confidence: 99%

“…When using this data as input for Eq. (3) the difference in the order of magnitude in S as compared to experiments is removed [13]. Thus, following the approach of Ref.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Critical Behavior of the Thermoelectric Transport Properties in Amorphous Systems near the Metal-Insulator Transition

Villagonzalo¹,

Röemer²,

Schreiber³

et al. 2001

Springer Proceedings in Physics

Self Cite

View full text Add to dashboard Cite

The scaling behavior of the thermoelectric transport properties in disordered systems is studied in the energy region near the metal-insulator transition. Using an energydependent conductivity σ obtained experimentally, we extend our linear-response-based transport calculations in the three-dimensional Anderson model of localization. Taking a dynamical scaling exponent z in agreement with predictions from scaling theories, we show that the temperature-dependent σ, the thermoelectric power S, the thermal conductivity K and the Lorenz number L0 obey scaling.The scaling description [1] of disordered systems, e.g. the Anderson model of localization, has cultivated our understanding of transport properties in such systems [2,3]. According to the scaling hypothesis, the behavior of the d.c. conductivity σ near the metal-insulator transition (MIT) in the Anderson model can be described by only a single scaling variable. As a result of the scaling theory, the dynamical conductivity in the three-dimensional (3D) Anderson model behaves as [4,5] where T is the temperature and t is the dimensionless distance from the critical point. For example, t = |1 − E F /E c | where E F and E c are the Fermi energy and the mobility edge, respectively. The parameter ν is the correlation length exponent, which in 3D is equivalent to the conductivity exponent, σ ∝ t ν , and z is the dynamical exponent, σ ∝ T 1/z . It was further demonstrated that not only σ(t, T ) obeys scaling in the 3D Anderson model but also the thermoelectric power S(t, T ) [6,7], the thermal conductivity K(t, T ) and the Lorenz number L 0 (t, T ) [7]. However, despite the quality of the scaling of σ, we obtained an unphysical value for z [7]. Scaling arguments for noninteracting systems predict z = d in d dimensions [4,5]. But we found [7] z = 1/ν ≪ 3. In addition, values of S(T ) [8,9] are at least an order of magnitude larger than in measurements of doped semiconductors [10] and amorphous alloys [11,12].In what follows, we show that we obtain the right order of magnitude [13] and good scaling for these thermoelectric transport properties by using a "modified" critical behavior of σ in the linear-response formulation for the Anderson model based on experimental data. ⋆ Permanent address: National Institute of Physics, University of the Philippines, Diliman, 1101 Q. C., PhilippinesIn the linear-response formulation, the thermoelectric transport properties can be determined from the kinetic coefficients L ij [9], i.e.,The L ij relate the induced charge and heat current densities to their sources such as a temperature gradient [9]. In the absence of interactions and inelastic scattering processes, the L ij are expressed as [14,15,16]for i, j = 1, 2, where µ is the chemical potential of the system, f (E, µ, T ) is the Fermi distribution function, and A(E) describes the system dependent features. In the Anderson model, one sets A(E) to be equal to the critical behavior of. Note, however, that this behavior near the MIT does not contain a T dependence. Hence, the...

show abstract

mentioning

confidence: 82%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

“…When using this data as input for Eq. (3) the difference in the order of magnitude in S as compared to experiments is removed [13]. Thus, following the approach of Ref.…”

mentioning

confidence: 99%

See 3 more Smart Citations