Non Fermi liquid signatures across strain engineered metal-insulator transition in line-graph lattices

TL;DR

This study explores how strain engineering induces non-Fermi liquid behavior and phase transitions in line-graph lattices, revealing complex interplay between electronic structure, magnetism, and thermal effects.

Contribution

It provides a detailed numerical analysis of strain-induced phase transitions and non-Fermi liquid signatures in flat band line-graph lattices, a novel insight into tunable correlated electron systems.

Findings

Identification of magnetic insulators, localized insulators, and non-Fermi liquid metals at low temperatures.

Quantification of magnetic transition scales and strain-tuned metal-insulator crossover scales.

Observation of variable transport scaling exponents across the phase transitions.

Abstract

Controlling the properties and thus the functionalities of correlated electron systems via externally tunable perturbations has always remained a cherished goal in quantum condensed matter physics. Recently, straintronics has proved to be one such external control which can dictate the quantum phases and transitions in materials via the reconstruction of their electronic band structure. A particularly intriguing scenario arises in the context of flat band line-graph lattices wherein straintronics is found to bring forth non trivial phase transitions. This paper reports the phase transitions and thermal scales across the Lieb/Kagome interconversion in the electronic interaction-strain-temperature space. Based on the thermodynamic, spectroscopic and transport signatures across the strain tuned interconversion of these line-graph lattices we have mapped out the low temperature phases and thermal transition scales, numerically determined using non perturbative calculations. While at the low temperatures, interaction-strain plane is spanned by magnetically correlated insulators, flat band induced weak transiently localized insulators and non Fermi liquid metallic phases, thermal fluctuations aid in to stabilize coexistent magnetic correlations. Apart from quantifying the magnetic transition scales in this system our results on the spectroscopic and transport signatures distill the strain tuned metal-insulator transition and crossover scales which exhibit variable transport scaling exponents.