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epl draft Effect of disorder on a Pomeranchuk instability
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ho, Andrew F. Schofield, Andrew J. |
| Copyright Year | 2009 |
| Abstract | We study the effect of weak and dilute disorder on the order parameter equation and transition temperature of a Pomeranchuk-type Fermi-surface instability using replica mean field theory. We consider the example of a phase transition to a dx2−y2 type Fermi surface distortion, and show that, in the regime where such a transition is second order, the transition temperature is reduced by disorder in essentially the same way as that for a d-wave superconductor. We argue that observing this disorder dependence of metal-to-metal transition is a useful indicator of a finite angular momentum Fermi surface distortion. Introduction. – In recent years a growing number of correlated systems have been found to exhibit thermodynamic phase transitions between metallic states. Examples include the 17K transition in URu2Si2 [1] and the transitions around the metamagnetic quantum critical endpoint of Sr3Ru2O7 [2]. In contrast to the more familiar superconducting or magnetic instabilities, the order parameter which presumably develops at these transitions appears to be transparent or only weakly coupled to most experimental probes. Thus identifying the nature of this “dark” or “hidden” order is a challenging problem. Many years ago Pomeranchuk [3] found a condition for instabilities between metallic states characterized by Fermi surface shape distortions. It has been argued that this instability occurs in quantum Hall systems [4, 5] and is the origin of the transitions in URu2Si2 [6] and Sr3Ru2O7 [2]. However, the key question remains how to identify this sort of order–particularly if bulk changes are masked by domains formation. In this Letter we calculate the form of the disorder dependence of the transition temperature and find it to have a characteristic signature of momentum space distortions of the metallic Fermi surface. We are motivated by the empirical similarity in the way the mysterious phase in the bilayer ruthenate, Sr3Ru2O7 [2], and the superconductivity in the related single-layer compound, Sr2RuO4 [7], are both eliminated with very low levels of disorder. In the latter case quantitative comparison of the strong disorder dependence of the superconducting transition temperature Tc to the wellknown form [8] has become the de-facto signature of nonzero orbital angular momentum pairing (in the absence of phase sensitive methods). In contrast s-wave superconductors are insensitive to disorder [9]. Could a similar dependence be used to diagnose the Pomeranchuk transition? In this Letter we show how the Pomeranchuk instability is an analogue of non s-wave superconductivity but in the particle-hole rather than particle-particle channel. We exploit this using a combination of standard methods to show that, not only might one similarly expect a sensitivity to disorder but that the precise form of the disorder dependence of Tc is, under certain circumstances, identical to that of unconventional superconductors. This provides a quantitative test of the “dark order” metallic phase which parallels that now used for unconventional superconductivity. Moreover, since we show that the Pomeranchuk instability is strongly suppressed in presence of weak disorder, our results may provide an explanation as to why this rather subtle metal to metal transition is not observed more often in nature. Model. – To study effects of disorder in a simple model of a Pomeranchuk instability, we consider electrons on a two dimensional (2D) tight-binding lattice with a quadrupolar interaction that has been studied extensively [10–13] |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://arxiv.org/pdf/0706.1955v2.pdf |
| Alternate Webpage(s) | http://export.arxiv.org/pdf/0706.1955 |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Analog AngularJS Blinded Communication endpoint Dietary Iron Distortion Electrons Femtometer Field electron emission Instability Kosterlitz–Thouless transition Molecular orbital Mood Disorders Parallels Desktop for Mac Phase Transition Population Parameter Position and momentum space Quantum Hall effect Quantum critical point Quantum field theory Superconductivity Technetium Thermodynamics Tight binding |
| Content Type | Text |
| Resource Type | Article |
