Observations of Dislocation Etch Pits in SmB6

Samarium hexaboride (SmB₆) is a strongly correlated topological insulator, showing insulating behavior from 4-40 K and a conduction plateau below 4 K due to the topological state. Recent transport results on the bulk have demonstrated that SmB₆ is not sensitive to point defects but extended defects such as one-dimensional dislocations may still be present. Such dislocations may provide an additional current path beside the topologically protected surface state. The one- dimensional dislocations must terminate on the surface and can be identified by the use of proper chemical etching. In order to characterize the bulk defects in SmB₆, we developed an etching technique using equal parts sulfuric acid and nitric acid. Using this etchant we found etch pits in the shape of inverted pyramids aligned with the crystalline axis, which are expected to indicate dislocations. In aluminum flux grown samples, dislocation etch pit densities range from 2x10⁶ to 9x10⁶ cm^-2. A comparison of flux grown samples and floating zone grown samples will be presented.