Title: Signatures of the Kondo effect in VSe2,
Abstract: VSe2 is a transition metal dichaclogenide which has a charge-density wave
transition that has been well studied. We report on a low-temperature upturn in
the resistivity and, at temperatures below this resistivity minimum, an unusual
magnetoresistance which is negative at low fields and positive at higher
fields, in single crystals of VSe2. The negative magnetoresistance has a
parabolic dependence on the magnetic field and shows little angular dependence.
The magnetoresistance at temperatures above the resistivity minimum is always
positive. We interpret these results as signatures of the Kondo effect in VSe2.
An upturn in the susceptibility indicates the presence of interlayer V ions
which can provide the localized magnetic moments required for scattering the
conduction electrons in the Kondo effect. The low-temperature behaviour of the
heat capacity, including a high value of gamma, along with a deviation from a
Curie-Weiss law observed in the low-temperature magnetic susceptibility, are
consistent with the presence of magnetic interactions between the paramagnetic
interlayer V ions and a Kondo screening of these V moments.