arXiv subjects

Bo-Sen Wang

Publications and source records attributed to Bo-Sen Wang.

3 recordsLinked to original sources

arXiv2026

Cs$_3$V$_9$Te$_{13}$: A Correlated Electron System with Topological Flat Bands

Correlated electron systems with topological flat bands show great promise in exploring exotic quantum phenomena. However, such crystalline materials remain rare. Here we report the discovery of a novel material, Cs$_3$V$_9$Te$_{13}$, which unexpectedly exhibits magnetism and significant electron correlations. The crystal structure features two interpenetrating sets of vanadium triangles that can be linked with an ideal kagome lattice. The physical property measurements demonstrate a cascade of correlated electron phenomena, including quasi-two-dimensional bad metal, non-Fermi-liquid behavior, antiferromagnetic spin-density-wave transition at $T_\mathrm{N}$ = 47 K, possible short-range spin ordering at $\sim$350 K, a large Sommerfeld coefficient of 246 mJ mol-fu$^{-1}$ K$^{-2}$, and pressure-induced quantum criticality. These correlated electron behaviors are associated with the topological flat bands at the Fermi level, the latter of which are generated from the V2 sublattice in terms of a bipartite kagome model. Our findings establish Cs$_3$V$_9$Te$_{13}$ as a brand new correlated matter that synergistically combines flat-band physics and tunable properties.

cond-mat.str-el↗

arXiv2025

Magnetism and Correlated Electrons in LaCr$_2$Ge$_2$N

We report the synthesis, structure and physical properties of a new quaternary nitride LaCr$_2$Ge$_2$N. The compound crystallizes in the CeCr$_2$Si$_2$C-type structure (P4/mmm), featuring distinctive Cr$_2$N square sheets within Cr$_2$Ge$_2$N block layers. Physical characterizations reveal enhanced electron correlations evidenced by a Sommerfeld coefficient substantially larger than band calculations and pressure-induced deviation from Fermi-liquid behavior. Magnetic measurements show short-range antiferromagnetic correlations developing around 460 K, followed by long-range magnetic ordering at 14 K. Additionally, subtle anomalies at 378 K suggest possible electronic ordering. First-principles calculations reveal nearly-flat Cr-3d bands near the Fermi level and predict a striped antiferromagnetic ground state. This work demonstrates how electron count variation in the CeCr$_2$Si$_2$C-type structure family leads to magnetic ordering in LaCr$_2$Ge$_2$N, contrasting with the paramagnetic behavior of LnCr$_2$Si$_2$C compounds.

cond-mat.str-el↗

arXiv2024

Superconductivity emerging from density-wave-like order in a correlated kagome metal

Unconventional superconductivity (USC) in a highly correlated kagome system has been theoretically proposed for years, yet the experimental realization is hard to achieve. The recently discovered vanadium-based kagome materials, which exhibit both superconductivity and charge density wave (CDW) orders, are nonmagnetic and weakly correlated, thus unlikely host USC as theories proposed. Here we report the discovery of a chromium-based kagome metal, CsCr$_3$Sb$_5$, which is contrastingly characterised by strong electron correlations, frustrated magnetism, and characteristic flat bands close to the Fermi level. Under ambient pressure, it undergoes a concurrent structural and magnetic phase transition at 55 K, accompanying with a stripe-like $4a_0$ structural modulation. At high pressure, the phase transition evolves into two transitions, probably associated with CDW and antiferromagnetic spin-density-wave orderings, respectively. These density-wave (DW)-like orders are gradually suppressed with pressure and, remarkably, a superconducting dome emerges at 3.65-8.0 GPa. The maximum of the superconducting transition temperature, $T_\mathrm{c}^{\mathrm{max}}=$ 6.4 K, appears when the DW-like orders are completely suppressed at 4.2 GPa, and the normal state exhibits a non-Fermi-liquid behaviour, reminiscent of USC and quantum criticality in iron-based superconductors. Our work offers an unprecedented platform for investigating possible USC in a correlated kagome system.

cond-mat.supr-con↗