Physical properties of KxNi2-ySe2 single crystals

TL;DR

This study synthesizes K0.95Ni1.86Se2 single crystals, revealing heavy-fermion-like behavior and a transition from a charge density wave state to a heavy fermion state below 30 K, with no superconductivity observed.

Contribution

First detailed physical property analysis of K0.95Ni1.86Se2 single crystals highlighting their unique electronic and magnetic behaviors compared to polycrystals.

Findings

Exhibit Fermi liquid behavior with heavy-fermion characteristics.

Transition from charge density wave to heavy fermion state below 30 K.

Absence of superconductivity in single crystals.

Abstract

We have synthesized K0.95(1)Ni1.86(2)Se2 single crystals. The single crystals contain K and Ni deficiencies not observed in KNi2Se2 polycrystals. Unlike KNi2Se2 polycrystals, the superconductivity is absent in single crystals. The detailed physical property study indicates that the K0.95Ni1.86Se2 single crystals exhibit Fermi liquid behavior with heavy-fermion-like characteristics. Transition from the high temperature local charge density wave state to heavy fermion state below T ~ 30 K results in an enhancement of electron-like carrier density whereas magnetic susceptibility shows little anisotropy and suggests presence of both itinerant and localized Ni orbitals.