YCr6Ge6 as a Candidate Compound for a Kagome Metal

TL;DR

This study investigates YCr6Ge6, a compound with a kagome lattice, revealing its potential as a kagome metal exhibiting correlated electronic phenomena through experimental measurements and band structure calculations.

Contribution

It is the first comprehensive analysis of YCr6Ge6 combining experimental and theoretical approaches to identify its kagome metal characteristics.

Findings

Moderately strong electron correlation indicated by enhanced Sommerfeld coefficient.

In-plane resistivity is twice the interplane resistivity, contrary to expectations.

Presence of flat bands near the Fermi level related to Cr 3d orbitals.

Abstract

We show that YCr6Ge6, comprising a kagome lattice made up of Cr atoms, is a plausible candidate compound for a kagome metal that is expected to exhibit anomalous phenomena such as flat-band ferromagnetism. Resistivity, magnetization, and heat capacity are measured on single crystals of YCr6Ge6, and band structure calculations are performed to investigate the electronic structure. Curie-Weiss-like behavior in magnetic susceptibility, T2 dependence in resistivity, and a Sommerfeld coefficient doubly enhanced from a calculated value indicate a moderately strong electron correlation. Interestingly, the in-plane resistivity is twice as large as the interplane resistivity, which is contrary to the simple expectation from the layered structure. Band structure calculations demonstrate that there are partially flat bands slightly below the Fermi level near the {\Gamma} point, which is ascribed to Cr 3d3z2-r2 bands and may govern the properties of this compound.