ABSTRACT
Properties of correlated states in a flat band are determined by the interplay of quantum geometry and interactions. Ideal quantum geometric properties, e.g., when the quantum metric becomes equal to the berry curvature, is vital for realizing exotic correlated phases like fractional topological states in an insulator. Here, we report the discovery of ideal quantum geometry in semimetals, exemplified by the surface states of rhombohedral graphite [arXiv: 2504.03617]. The drumhead region of the surface states of rhombohedral graphite has the local inequality between quantum metric and Berry curvature saturated; therefore, its two surface bands mimic a pair of Landau levels, but in the absence of magnetic fields. As a consequence, the stiffness of correlated states (e.g., superfluid stiffness of superconducting order and spin stiffness of magnetic orders) has a finite contribution from the center of the drumhead region. In particular, we illustrate this using the superfluid stiffness of the superconducting state, and show that the superfluidity in rhombohedral graphite is analogous to that in heavy fermion compounds.
BIOGRAPHY
Dr. Guodong Jiang is currently a postdoc at Aalto University, Finland, working with Prof. Päivi Törmä. His research is focused on the area of condensed matter theory, especially superconductivity and correlated phenomena. Dr. Jiang received his BS from Nankai University in 2014 and his PhD from Purdue University in 2021. He then worked as a postdoc at the University of Nevada, Reno, from 2021-2023 before joining his current position in 2023.
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