Synthesizing SmB6 single crystals by various techniques

Samarium Hexaboride (SmB6), a mixed valence Kondo insulator, has attracted much recent attention due to the discovery of a low temperature conducting surface state, proposed to be a topologically protected surface state that arises due to the formation of a Topological Kondo insulator state. To date, single crystals of SmB6 have only been synthesized by ‘aluminum flux’ and ‘floating zone’ methods, mainly due to the high melting point of boron. Recently, quantum oscillations were observed in the both type of crystals, but intrinsic origins of those findings are controversial due to possible extrinsic origins such as aluminum inclusions. Therefore, growing single crystals using alternative methods is considered important for elucidating the intrinsic electronic properties of SmB6. We will discuss efforts to produce SmB6 single crystals by radiofrequency (RF) technique and by flux growth methods using alternative fluxes, comparing the results of various techniques.