We construct a simple holographic model incorporating higher-order coupling terms for electron self-interactions. It can exhibit typical behavior of a Mott insulator, including a metal-insulator transition and a decrease in dc conductivity with the increase of charge density. In the analysis of ac conductivity, a soft gap is generally observed. Notably, when the dc conductivity approaches zero, the ac conductivity reveals a multipeak structure, which can be attributed to the Mott and charge-transfer gaps observed experimentally in transition metals. With the increase of dc conductivity, the multipeak structure gradually reverts to soft-gap behavior or even metallic conductivity. The accuracy of the numerical result is guaranteed by $\sigma (\omega \to 0)={\sigma }_{dc}$ and sum rules.

Close

PrevNext

View figure in article

• Electrical conductivity
• General relativity
• Charge-transfer insulators
• Mott insulators
• Duality