Real-Time Observation of Phonon-Mediated σ-π Interband Scattering in MgB_{2}

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Optics

Background:

• Anisotropic electronic structures in layered materials like graphite and graphene exhibit unique responses to light.
• Coherent stimulation of bosonic modes can lead to exotic electronic properties.

Purpose of the Study:

• To investigate the selective enhancement of E_{2g} phonons in the multiband superconductor Magnesium Diboride (MgB2) using femtosecond laser pulses.
• To demonstrate transient control over the carrier number in the σ-electronic subsystem of MgB2.
• To elucidate the σ-π interband scattering mechanism in MgB2 under non-equilibrium conditions.

Main Methods:

• Impulsive light excitation using femtosecond laser pulses.
• Monitoring non-equilibrium evolution of optical constants in the spectral region of a- and c-axis plasma frequencies.
• Theoretical modeling to understand the observed phenomena.

Main Results:

• Selective enhancement of E_{2g} phonons in MgB2 was achieved.
• Transient control of carrier density in the σ-electronic subsystem was observed.
• Detailed insights into the σ-π interband scattering mechanism were obtained through optical constant analysis.

Conclusions:

• Femtosecond laser pulses offer a pathway for selective phonon population and transient control of electronic properties in anisotropic materials.
• The study provides a deeper understanding of non-equilibrium dynamics and electron-phonon coupling in MgB2.
• This approach opens possibilities for manipulating emergent electronic properties in superconductors and related materials.