Universität zu Köln

Weiss, Philipp S., Narozhny, Boris N., Schmalian, Joerg ORCID: 0000-0003-4142-2448 and Woelfle, Peter (2016). Interference of quantum critical excitations and soft diffusive modes in a disordered antiferromagnetic metal. Phys. Rev. B, 93 (4). COLLEGE PK: AMER PHYSICAL SOC. ISSN 1550-235X

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Abstract

We study the temperature-dependent quantum correction to conductivity due to the interplay of spin density fluctuations and weak disorder for a two-dimensional metal near an antiferromagnetic (AFM) quantum critical point. AFM spin density fluctuations carry large momenta around the ordering vector Q and, at lowest order of the spin-fermion coupling, only scatter electrons between hot spots of the Fermi surface which are connected by Q. Earlier, it was seen that the quantum interference between AFM spin density fluctuations and soft diffusive modes of the disordered metal is suppressed, a consequence of the large-momentum scattering. The suppression of this interference results in a nonsingular temperature dependence of the corresponding interaction correction to conductivity. However, at higher order of the spin-fermion coupling, electrons on the entire Fermi surface can be scattered successively by two spin density fluctuations and, in total, suffer a small momentum transfer. This higher-order process can be described by composite modes which carry small momenta. We show that the interference between formally subleading composite modes and diffusive modes generates singular interaction corrections which ultimately dominate over the nonsingular first-order correction at low temperatures. We derive an effective low-energy theory from the spin-fermion model which includes the above-mentioned higher-order process implicitly and show that for weak spin-fermion coupling the small-momentum transfer is mediated by a composite propagator. Employing the conventional diagrammatic approach to impurity scattering, we find the correction delta sigma proportional to + 1n(2) T for temperatures above an exponentially small crossover scale.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Weiss, Philipp S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Narozhny, Boris N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schmalian, Joerg UNSPECIFIED orcid.org/0000-0003-4142-2448 UNSPECIFIED Woelfle, Peter UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-287081
DOI:	10.1103/PhysRevB.93.045128
Journal or Publication Title:	Phys. Rev. B
Volume:	93
Number:	4
Date:	2016
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	1550-235X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language RESISTIVITY; CONDUCTIVITY; LOCALIZATION; SYSTEMS Multiple languages Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/28708