LM thesis proposal
Supervisor: Giacomo Baldi
In the last years, phase-change non-volatile memory devices have risen important attention for technological applications [1]. They are made by phase-change materials (PCMs), a class of functional materials that are reversibly and rapidly switched between amorphous and crystalline states by electrical pulses in a short timescale of a few nanoseconds. While their crystalline state has been largely investigated, little is still known on the properties of their amorphous state due to the intrinsic difficulties related to the study of materials far from the thermodynamic equilibrium with both numerical simulations and experiments. Several studies have identified the existence of some remarkable anomalous behaviours in the amorphous state (like physical aging, secondary relaxation processes and dynamical transitions), which may play an important role in determining their switching kinetics [2,3]. The comprehension of the glassy state is therefore extremely important for both technological applications and fundamental science.
The proposed thesis work will be focused on the investigation of the relaxation dynamics of amorphous Ge15Te85, a classical example of PCM material. The main part of the work will be developed during a one-week experiment at the Hamburg Synchrotron radiation facility PetraIII, exploiting the technique of X-ray Photon Correlation Spectroscopy (XPCS), complemented by laboratory-based methods in Trento.
References
- S. Wei, P. Lucas, and C. A. Angell, MRS Bull. 44, 691 (2019).
- J. Y. Raty et al. Nat. Commun. 6, 7467 (2015).
- N. Amini et al. Mat. Sc. Semic. Process. 135,106094 (2021).
Starting date: 01/02/2023
