Dresden 2011 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 3: CE: Charge Density Wave \& Peierls Instability
TT 3.10: Talk
Monday, March 14, 2011, 13:00–13:15, HSZ 304
Collective excitations and low temperature transport properties of bismuth — •Piotr Chudzinski and Thierry Giamarchi — DPMC-MaNEP, University of Geneva, 24 Quai Ernest-Ansermet CH-1211 Geneva, Switzerland
We examine the influence of collective excitations on several transport coefficients (conductivitiy, magneto-optical conductivity, Nernst effect) for semimetal, bismuth. A longstanding problem of the transport coefficients in this material is the fact that their amplitude and temperature dependences do not obey naive Fermi liquid expectations. For the conductivity, we show that at high temperatures Baber scattering is able to explain quantitatively the DC resistivity experiments, while at low temperatures many-body effects need to be introduced to explain qualitative deviations from the standard T2 behavior. An atypical feature in magneto-optical conductivity is predicted. The Nernst effect in bismuth was recently the subject of several contradictory theoretical studies. We show that a plasmon physics allows to get a coherent picture and leads to very large values of the Nernst signal. We use two complementary methods- Feynmann diagrams and field theory (Hubbard-Stratonovich transformation). These methods, which go beyond the standard RPA study, allow to set a limit to the validity of our model and to make contact with the other family of semimetals, 1T−TiSe2, also subject of recent experimental interest. To complete the discussion of semimetals, we also study the case of graphite.