Phase separation in the vicinity of Fermi surface hot spots

Abstract

The authors reveal an intimate relationship between intrinsic impurities and Fermi surface topology as a previously overlooked degree of freedom for understanding the emergence of complex electronic landscapes in the prominent transition metal dichalcogenide 1$T$-TiSe${}_{2}$. They find a fundamental tendency towards phase separation in the vicinity of Fermi surface hot spots, which are locations in reciprocal space with band crossings close to, but not at, the Fermi level. The study highlights the key role of the Fermi surface topology for driving phase-separated states that emerge upon doping or pressure in many transition metal dichalcogenides and other charge density wave compounds.