We performed point-contact spectroscopy tunneling measurements on ${\mathrm{Cu}}_x\mathrm{TiSe}{}_2$ bulk with $x=0.02$ and $0.06$ at temperatures ranging from $T=4-40$ K and observe a suppression in the density of states around zero bias that we attribute to enhanced Coulomb interactions due to disorder. We find that the correlation gap associated with this suppression is related to the zero-temperature resistivity. We use our results to estimate the disorder-free transition temperature and find that the clean limit $T_{c0}$ is close to the experimentally observed $T_c$ at optimal doping.

• Received 10 September 2014
• Revised 29 January 2015

DOI:https://doi.org/10.1103/PhysRevB.91.094509