Investigations on pseudogap semimetal CoSi

The theoretically proposed pseudogap semimetal CoSi has been investigated by detailed experimental studies of magnetotransport, calorimetric and thermopower measurements. The two parallel resistor model is applied to understand its semimetal nature. The obtained gap is around 13 meV. The conduction process is explained by the single relaxation method by implementing Kohler's rule, , . The excess heat capacity is a consequence of thermally activated behaviour across the gap and the calculated is about . At K, the metallic behaviour without the gap, vanishing of excess heat capacity, reasonable metallic value of and linear diffusion thermopower, signifies the closure of pseudogap. The correlation amongst the T-dependent features of resistivity, excess heat capacity and thermoelectric power reveals the hidden metal-to-insulator transition in CoSi. The high magnetoresistance at low temperatures is reported to arise due to Lorentz force and its applications as a low temperature magnetic field sensor is also discussed.