The interplay between spin and charge degrees of freedom in Mott insulators remains a central topic in strongly correlated electron systems.Using variable-temperature scanning tunneling microscopy/spectroscopy,we inve...The interplay between spin and charge degrees of freedom in Mott insulators remains a central topic in strongly correlated electron systems.Using variable-temperature scanning tunneling microscopy/spectroscopy,we investigate the Van der Waals magnet RuBr_(3),a candidate Kitaev quantum spin liquid material.At low temperatures,RuBr_(3) exhibits a large correlated Mott gap exceeding 3 eV.As temperature increases,the gap softens significantly,decreasing to -0.7 eV by 200 K.This evolution coincides with magnetic phase transitions:a sharp reduction occurs near the Neel temperature(T_(N)≈34 K)upon loss of long-range antiferromagnetic order,followed by a gradual decline through the Kitaev paramagnetic regime.Comparison with α-RuCl_(3) reveals that the dominant spin correlations—whether long-range order or short-range Kitaev interactions—govern the Mott gap renormalization.Our results highlight the essential role of spin-charge coupling in Mott physics and provide key insights into the electronic behavior of Kitaev materials across different magnetic phases.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12474002 and 22171283 for R.Y.)the National Key Research and Development Program of China(Grant Nos.2024YFA1409002 for R.R.D.and 2023YFA1406000 for R.Y.)+2 种基金the Quantum Science and Technology–National Science and Technology Major Project(Grant No.2021ZD0302600 for R.R.D.)the Open Research Fund of State Key Laboratory of Materials for Integrated Circuits(Grant No.SKLJC-K2025-05 for X.H.Z.)the Innovation Program for Quantum Science and Technology(Grant No.2023ZD0300500 for X.H.Z.)。
文摘The interplay between spin and charge degrees of freedom in Mott insulators remains a central topic in strongly correlated electron systems.Using variable-temperature scanning tunneling microscopy/spectroscopy,we investigate the Van der Waals magnet RuBr_(3),a candidate Kitaev quantum spin liquid material.At low temperatures,RuBr_(3) exhibits a large correlated Mott gap exceeding 3 eV.As temperature increases,the gap softens significantly,decreasing to -0.7 eV by 200 K.This evolution coincides with magnetic phase transitions:a sharp reduction occurs near the Neel temperature(T_(N)≈34 K)upon loss of long-range antiferromagnetic order,followed by a gradual decline through the Kitaev paramagnetic regime.Comparison with α-RuCl_(3) reveals that the dominant spin correlations—whether long-range order or short-range Kitaev interactions—govern the Mott gap renormalization.Our results highlight the essential role of spin-charge coupling in Mott physics and provide key insights into the electronic behavior of Kitaev materials across different magnetic phases.
