8105
Prediction and discovery Time-reversal symmetry protected ( but not topologically protected ) edge states were predicted to occur in quantum well s ( very thin layers ) of mercury telluride sandwiched between cadmium telluride ( band inversion in Hg ( Cd ) Te was first reported in 1986 by Pankratov and collaborators ) , and were observed in 2007 .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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