Determination of tilt degree and Weyl-node separation by the spatial Imbert-Fedorov shift near the Brewster angle

Abstract

The Imbert-Fedorov (IF) shift at the optical interface of Weyl semimetal (WSM) is extremely significant to recognize the optical characteristics of WSM. In this paper, we have studied the spatial IF shift on the surface of a bulk WSM by theoretically deriving a 4 \ifmmode\times\else\texttimes\fi{} 4 magneto-optic matrix. It is found that the phenomenon of spatial IF shift changing from positive to negative occurs at an incident angle near the Brewster angle. Remarkably, this special phenomenon can be regulated by changing the frequency of incident light, tilt degree, and Weyl node separation. Specially, for a fixed Weyl node separation, the phenomena of spatial IF shift changing from positive to negative can be realized at different tilt degrees by simply changing the frequency, and there exists one-to-one correspondence between the tilt degree and frequency at these situations. Similarly, for a fixed tilt degree, these phenomena can be achieved at different Weyl node separations by changing the frequency, and there also exists one-to-one correspondence between the Weyl node separation and frequency. Therefore, these tunable phenomena of spatial IF shift changing from positive to negative enable the feasibility of accurate determination of tilt degree and Weyl node separation. Our study can also provide a reference for the research of IF shift in such similar structures.