Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 56: Correlated Electrons: Quantum-Critical Phenomena – Theory
TT 56.1: Vortrag
Mittwoch, 18. März 2015, 09:30–09:45, A 053
Superconductivity and charge order near the onset of antiferromagnetism in metals — •Max Henner Gerlach1, Yonathan Schattner2, Simon Trebst1, and Erez Berg2 — 1University of Cologne, Germany — 2Weizmann Insitute of Science, Rehovot, Israel
The quantum-critical transition of a system of itinerant electrons into an antiferromagnetically ordered phase has long been believed to play an important role in the physics of superconductors such as the electron-doped cuprates and the iron pnictides. The complete understanding of this quantum-critical point has remained a key challenge for both analytical and numerical approaches. On the computational side, a numerically exact simulation of such fermionic systems via quantum Monte Carlo studies has long been precluded by the infamous negative sign problem. Only recently a way has been found to set up sign-problem-free simulations of lattice models that realize the universal physics close to this phase transition [1].
Building upon this conceptual work, we introduce further improvements to the Monte Carlo sampling techniques adapted to such a model, allowing us to better understand the properties of the quantum-critical point and the instability towards d-wave-like superconductivity in its vicinity. In addition, we study a competing instability towards a charge-density-wave-like order, which we support by a supplementary interaction. Taken together, our results further improve our understanding of the rich physics of a relatively simple single-band electron model appropriate for the cuprates.
[1] E. Berg, M. A. Metlitski, and S. Sachdev,
Science 338, 1606 (2012)