The semiconductor SnSe hosts a unique multivalley electronic band structure, offering rich physical phenomena for various applications. Especially its excellent thermoelectric properties are ceaselessly under great attention. By employing pressure-dependent infrared spectroscopy combined with density functional theory calculations, the evolution of the multivalley is mapped under external pressure for different self-dopings. The presented diagram summarizes the findings. In lightly doped SnSe, a phase transition from a semiconductor to a semimetal is observed by increasing the pressure. However, for heavily doped SnSe, altering the Fermi surface, successive Lifshitz transitions take place under pressure, further activating the multivalley physics.
- Tobias Biesner
- Weiwu Li
- Martin Dressel
