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Orbital- and atom-dependent linear dispersion across the Fermi level induces charge density wave instability in EuTe4
Journal
Physical Review B
ISSN
24699950
Date Issued
2022-01-15
Author(s)
Pathak, Abhishek
Gupta, Mayanak K.
Mittal, Ranjan
Bansal, Dipanshu
Abstract
In the Peierls description of a charge density wave (CDW), Fermi surface nesting (FSN) - defined by the divergence of the imaginary part of electronic susceptibility, i.e., Im{χ0} - leads to divergence of the real part, thus inducing CDW instability at wave vector qCDW. Here we show that the divergence of Im{χ0} implying a divergence of Re{χ0} at the same qCDW breaks down for three-dimensional Fermi surfaces and is particularly severe for linearly dispersing electronic bands across the Fermi level (EF), as exemplified by rare-earth tellurides RTen. By calculating the orbital-, atom-, and momentum-resolved contribution to χ0 of EuTe4, we find that FSN and CDW instability are not driven by the same atoms and orbitals but from different ones. This unique behavior is enabled by linearly dispersing bands across EF with constant Fermi surface velocity that assists electron-hole pairs to form not only at EF but also across EF at qCDW, hence allowing different orbitals to contribute to the divergence of Re{χ0} and Im{χ0}. The above scenario is general and applicable to recent observations of CDWs and spin density waves (SDWs) from linearly dispersing bands in several Dirac and Weyl semimetals and kagome metals. Moreover, as we demonstrate, such component-resolved analysis provides focused input to engineer CDW and SDW states.