Indication of band flattening at the Fermi level in a strongly correlated electron system

Abstract

Using ultra-high quality SiGe/Si/SiGe quantum wells at millikelvin temperatures, we experimentally compare the energy-averaged effective mass, $m$, with that at the Fermi level, $m_F$, and verify that the behaviours of these measured values are qualitatively different. With decreasing electron density (or increasing interaction strength), the mass at the Fermi level monotonically increases in the entire range of electron densities, while the energy-averaged mass saturates at low densities. The qualitatively different behaviour reveals a precursor to the interaction-induced single-particle spectrum flattening at the Fermi level in this electron system.

References in corpus (8)

• Metal-insulator transition in two-dimensional electron systems
• Coulomb Correlations and the Wigner-Mott Transition
• Effective mass suppression in dilute, spin-polarized two-dimensional electron systems
• Ultra-high mobility two-dimensional electron gas in a SiGe/Si/SiGe quantum well
• Valley polarization assisted spin polarization in two dimensions
• Probing Electron Interactions in a Two-Dimensional System by Quantum Magneto-Oscillations
• Two dimensional electrons in (100) oriented silicon field effect structures in the region of low concentrations and high mobilities
• The effective electron mass in high-mobility SiGe/Si/SiGe quantum wells

Cited by in corpus (20)

• Graphite, graphene and the flat band superconductivity
• Exotic Lifshitz transitions in topological materials
• Transport evidence for a sliding two-dimensional quantum electron solid
• Quantum phase transition in ultrahigh mobility SiGe/Si/SiGe two-dimensional electron system
• Recent developments in the field of the metal-insulator transition in two dimensions
• Flat band and Planckian metal
• Metal-insulator transition and low-density phases in a strongly-interacting two-dimensional electron system
• Unusual anisotropy of inplane field magnetoresistance in ultra-high mobility SiGe/Si/SiGe quantum wells
• Fermion condensation, $T$-linear resistivity and Planckian limit
• Two-dimensional system of strongly interacting electrons in silicon (100) structures
• Metallic state in a strongly interacting spinless two-valley electron system in two dimensions
• Manifestation of strong correlations in transport in ultra-clean SiGe/Si/SiGe quantum wells
• Spin independence of the strongly enhanced effective mass in ultra-clean SiGe/Si/SiGe two-dimensional electron system
• Collective depinning and sliding of a quantum Wigner solid in a 2D electron system
• Valley effects on the fractions in an ultrahigh mobility SiGe/Si/SiGe two-dimensional electron system
• Spin effect on the low-temperature resistivity maximum in a strongly interacting 2D electron system
• Triple-top-gate technique for studying the strongly interacting 2D electron systems in heterostructures
• Band Flattening and Landau Level Merging in Strongly-Correlated Two-Dimensional Electron Systems
• Spin and valley effects on the quantum phase transition in two dimensions
• Quantum Wigner solid in two-dimensional electron systems in semiconductors