Universität zu Köln

Classen, Laura, Chubukov, Andrey, V, Honerkamp, Carsten and Scherer, Michael M. (2020). Competing orders at higher-order Van Hove points. Phys. Rev. B, 102 (12). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2469-9969

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Abstract

Van Hove points are special points in the energy dispersion, where the density of states exhibits analytic singularities. When a Van Hove point is close to the Fermi level, tendencies towards density wave orders, Pomeranchuk orders, and superconductivity can all be enhanced, often in more than one channel, leading to a competition between different orders and unconventional ground states. Here we consider the effects from higher-order Van Hove points, around which the dispersion is flatter than near a conventional Van Hove point, and the density of states has a power-law divergence. We argue that such points are present in intercalated graphene and other materials. We use an effective low-energy model for electrons near higher-order Van Hove points and analyze the competition between different ordering tendencies using an unbiased renormalization-group approach. For purely repulsive interactions, we find that two key competitors are ferromagnetism and chiral superconductivity. For a small attractive interaction, we find an unconventional spin Pomeranchuk order, in wich the spin oder parameter winds around the Fermi surface. The supermetal state, predicted for a single higher-order Van Hove point, is an unstable fixed point in our case.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Classen, Laura UNSPECIFIED UNSPECIFIED UNSPECIFIED Chubukov, Andrey, V UNSPECIFIED UNSPECIFIED UNSPECIFIED Honerkamp, Carsten UNSPECIFIED UNSPECIFIED UNSPECIFIED Scherer, Michael M. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-318403
DOI:	10.1103/PhysRevB.102.125141
Journal or Publication Title:	Phys. Rev. B
Volume:	102
Number:	12
Date:	2020
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	2469-9969
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language FUNCTIONAL RENORMALIZATION-GROUP; FERMI-SURFACE; SUPERCONDUCTIVITY Multiple languages Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/31840