Polarization-controlled multistate thermal conductivity in ferroelectric HfO2 thin films

While nanoscale electronic logic circuits are well-established, the development of nanoscale thermal logic circuits has been slow, mainly due to the absence of efficient and controllable nonvolatile field-effect thermal transistors. In this study, we investigate polarization-dependent thermal conductivity in ferroelectric orthorhombic hafnium dioxide (o-HfO2) thin films. Using molecular dynamics simulations with machine learning potentials, we show that a 24-nm-long o-HfO2 film can exhibit four distinct and stable thermal conductivity states arising from different ferroelectric polarization configurations. Notably, these states achieve a maximum switching ratio of 160.8% under 2% tensile strain. Our results suggest a practical pathway toward nonvolatile field-effect thermal transistors.