Dresden 2003 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 22: Metall-Isolator-Überg
änge in Quantensystemen II
TT 22.3: Vortrag
Freitag, 28. März 2003, 10:45–11:00, HSZ301
Low-temperature Peierls Gaps and Spectral Functions of a Quasi-One-Dimensional Metal — •Jörg Schäfer, Michael Sing, and Ralph Claessen — Institut für Physik, Universität Augsburg, 86135 Augsburg
Angle-resolved photoemission (ARPES) has been used to analyze the low-temperature electronic properties of the charge density wave (CDW) compound NbSe3 down to 15 K. The Fermi surface is explored k-resolved for the opening of the two Peierls gaps, and ARPES spectral functions of the nesting locations are presented. A ubiquitous pseudogap background is detected. The gap spectra A(kF,ω) relevant for the q1 and q2 CDWs exhibit maxima at binding energies of ∼ 110 meV and ∼ 45 meV, respectively. The Fermi surface remains partially metallic and, in addition, carries the signature of a quasiparticle renormalization. The energy scale of this effect is comparable to the full Peierls gap of the T2 distortion and vanishes above the transition. Possible mechanisms leading to this correlation with the CDW state are discussed.