Ideal quantum geometry of the surface states of rhombohedral graphite and its effects on the surface superconductivity

Fuente: arXiv
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Main Authors: Jiang, Guodong, Heikkilä, Tero, Törmä, Päivi
Format: Preprint
Published: 2025
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author Jiang, Guodong
Heikkilä, Tero
Törmä, Päivi
author_facet Jiang, Guodong
Heikkilä, Tero
Törmä, Päivi
contents The interplay of quantum geometry and interactions determines the correlated state properties of flat bands. Here, we investigate the ideal quantum geometry (IQG), i.e., the property that the trace of quantum metric equals the Berry curvature, in the surface flat bands of rhombohedrally stacked graphene (RG) multilayers. We show that RG represents a class of semimetals with IQG, among which only RG has a nonvanishing IQG at the center of the surface bands. In the presence of long-range hoppings, a displacement field polarizes the electron density to one of the two surfaces, stabilizing the IQG and boosting transitions to correlated phases like superconductivity. Analyzing the superfluid stiffness of the superconducting state in a many-layer RG, we reveal a heavy-fermion picture where the "heavy electrons" carry a nonzero supercurrent. This unusual behavior arises from the IQG of the surface states, which suggests a large fraction of supercurrent running on the surface of RG.
format Preprint
id arxiv_https___arxiv_org_abs_2504_03617
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Ideal quantum geometry of the surface states of rhombohedral graphite and its effects on the surface superconductivity
Jiang, Guodong
Heikkilä, Tero
Törmä, Päivi
Mesoscale and Nanoscale Physics
Superconductivity
The interplay of quantum geometry and interactions determines the correlated state properties of flat bands. Here, we investigate the ideal quantum geometry (IQG), i.e., the property that the trace of quantum metric equals the Berry curvature, in the surface flat bands of rhombohedrally stacked graphene (RG) multilayers. We show that RG represents a class of semimetals with IQG, among which only RG has a nonvanishing IQG at the center of the surface bands. In the presence of long-range hoppings, a displacement field polarizes the electron density to one of the two surfaces, stabilizing the IQG and boosting transitions to correlated phases like superconductivity. Analyzing the superfluid stiffness of the superconducting state in a many-layer RG, we reveal a heavy-fermion picture where the "heavy electrons" carry a nonzero supercurrent. This unusual behavior arises from the IQG of the surface states, which suggests a large fraction of supercurrent running on the surface of RG.
title Ideal quantum geometry of the surface states of rhombohedral graphite and its effects on the surface superconductivity
topic Mesoscale and Nanoscale Physics
Superconductivity
url https://arxiv.org/abs/2504.03617