Density of states features in some anomalous melting elements

Area of Science:

• Condensed matter physics
• Materials science
• Solid-state physics

Background:

• Understanding the electronic structure of materials in different phases (solid, liquid) is crucial for predicting their properties.
• Photoemission spectroscopy is a powerful technique for probing the electronic states of materials.

Purpose of the Study:

• To investigate the changes in electronic band structure during the melting process of crystalline metals.
• To differentiate between normal and anomalous melting behaviors using photoemission spectroscopy.

Main Methods:

• Valence band photoemission spectroscopy was performed on crystalline and liquid gallium, bismuth, and indium.
• Angle-integrated measurements were conducted using photon energies of 21.21 eV and 40.81 eV.

Main Results:

• Melting destroys Bloch states in all studied metals, leading to a free electron gas within a charge-neutral liquid.
• Indium exhibited minimal spectral changes upon solidification, suggesting a conserved electronic structure between its solid and liquid phases.
• Supercooled gallium and bismuth showed significant electronic structure alterations upon melting, forming pseudogaps at the Fermi energy (EF).

Conclusions:

• Photoemission spectroscopy can distinguish between normal and anomalous melting based on the observed changes in electronic structure.
• The formation of pseudogaps in gallium and bismuth indicates anomalous melting, while indium's behavior suggests normal melting.