  Topological insulator is a recently discovered class of material with
topologically protected surface state. YbB6 is predicted to be moderately
correlated Z2 topological insulator similar to SmB6. Here, I experimentally
test the resistance property of bulk YbB6 to verify its topological property.
By changing the thickness of YbB6, I found out that although the data curves
did not completely conform to the theory of topology, the experimental
observation to the overall trend showed a similar topological phenomenon.
