Giant Magnetothermal Conductivity Switching in WSi₂ Single Crystals Across a Broad Temperature Range

The ability to mitigate the flow of heat in a material through external stimuli, such as a magnetic or electric field, allow for the construction of solid-state heat switches to be used in a variety of applications in heat management, power generation and cooling.¹ In the proposed talk, we will present evidence of high purity ⍺-WSi₂ single crystal’s possession of a large magnetoresistance impacting thermal conductivity at temperatures below 100K. It also was found that at temperatures below 20K, the thermal conductivity switching ratio is >6 when under a magnetic field between 0T and 9T due to the depreciation of electron phonon scattering rates and with an experimental magnetoresistance of 2200-3500% generated through electron-hole compensation. Our measurements produced values for thermal conductivity and electrical conductivity which align with the theoretical approximation of the Lorenz number, as well as a finding that a 5-mm sample yields a thermal conduction switching speed of from 1 x 10^-4 seconds at 5K to 0.2 seconds at 100K. The magnitude of high purity ⍺-WSi₂ single crystal’s performance in both magnetoresistance and switching ratio supports the material be implemented as a thermal regulator in a solid-state heat switch.