Abstract
The Ising nematic quantum critical point associated with the zero-temperature transition from a symmetric to a nematic metal is an exemplar of metallic quantum criticality. We carry out a minus-sign-free quantum Monte Carlo study of this quantum critical point for a two-dimensional lattice model with sizes up to sites. For the parameters in this study, some (but not all) correlation functions exhibit scaling behavior over the accessible ranges of temperature, (imaginary) time, and distance, and the system remains nonsuperconducting down to the lowest accessible temperatures. The observed scaling behavior has remarkable similarities to recently measured properties of the Fe-based superconductors proximate to their putative nematic quantum critical point.
18 More- Received 26 November 2015
DOI:https://doi.org/10.1103/PhysRevX.6.031028
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Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
Numerous materials exhibit quantum phase transitions at which physical properties at absolute zero temperature change dramatically with small changes of a physical parameter such as pressure or chemical doping. Here, we present the first exact theoretical study of a quantum phase transition in a model metallic system and observe behaviors that are strikingly similar to those observed in several widely studied families of high-temperature superconducting materials.
In contrast to prior work on this problem that has relied on (often uncontrolled) approximate calculations, we apply an exact numerical method called determinant quantum Monte Carlo. We study a simple model on a square lattice that describes an Ising nematic quantum phase transition, where the system spontaneously breaks the symmetry between the horizontal and vertical lattice directions. Such transitions are observed in most iron-based high-temperature superconductors. We find that the quantum phase transition in our model is continuous and that its properties are fundamentally different from those of an Ising nematic transition in an insulator.
Our work paves the way for a deeper understanding of quantum critical phenomena in metals, a frontier problem in theoretical physics with broad applications in the field of quantum materials.