Kondo driven suppression of charge density wave in Van der Waals material UTe$_3$

Abstract

Competing electronic instabilities lie at the heart of emergent phenomena in quantum materials. In low-dimensional metals, Fermi-surface nesting can drive charge density wave (CDW) formation through a Peierls-like mechanism, while in strongly correlated systems, Kondo hybridization reconstructs the electronic structure by entangling localized moments with itinerant electrons. How these two fundamentally different instabilities interact$-$whether they coexist, compete, or mutually exclude each other$-$remains an open question. Here, we present suppression of charge density wave via the Kondo interaction in van der Waals material UTe$_3$. The angle-resolved photoemission spectroscopy (ARPES) data reveals Fermi surface nesting under similar conditions as seen in RETe$_3$ compounds. Despite that, no CDW is found in UTe$_3$ after an extensive search. We demonstrate that strong hybridization between U 5$f$ electrons and Te $p$ states reconstructs the low-energy electronic structure, removes the instability, and preempts CDW formation. Our results reveal a rare example where Kondo hybridization preempts density wave formation, offering a new route to controlling ordering phenomena in correlated 2D materials.

Figures (6)

• Figure 1: Characterization of UTe$_3$ (a) Resistivity of a bulk sample of UTe$_3$. (b) Resistivity of a thin flake of UTe$_3$. The inset shows the flake stacked on top of Cr/Au bottom contacts. The red scale bar is 30 $\mu$m. (c) Heat capacity of UTe$_3$ from 250 to 380 K. The dashed line is the heat capacity of TbTe$_3$ma2025thermoelectric, showing its CDW transition as comparison. (d) X-ray diffraction of a single crystal sample of UTe$_3$ at 10 K. (e) In-plane TEM diffraction pattern of UTe$_3$ at 92 K. (f) Neutron diffraction rocking curve near Q = (0, K, 1) measured various temperatures.
• Figure 2: Off-resonance ARPES and single Te-plane contribution to the electronic structure of UTe$_3$. (a) Schematic of the single Te layer Fermi surface contours (solid) and BZ (black) compared to the bulk zone-folded BZ (red) with additional zone-folded FS contours (dashed). (b) Wide valence band dispersion image along $X-\Gamma-X$ with comparison to DFT theory bands for bulk UTe$_3$. (c) Wide FS map spanning multiple bulk Brillouin zones, measured at 92 eV at 10 K where U 5$f$ spectral weight is suppressed. Over-plotted are the BZ boundaries and constant energy contours from a single square-net Te plane. (d) Wide 92 eV map for a constant energy of -0.3 eV below $E_F$ that highlights zone-folded band intensities from the two Te-layer bulk structure. (e) Series of energy band cuts at the (red) lines indicated in (c), illustrating the non-gapped $E_F$ crossings all along the Te layer FS contour.
• Figure 3: On-resonant ARPES electronic structure of U 5$f$ states and temperature dependence. (a) Constant energy slices of a 98 eV map at 10K highlighting different confined regions of U 5f weight: outer rectangular regions at $E_F$, and a square zone-center region at -20 meV. The Te-$p$ dispersion band is highlighted at -0.15 eV. Overplotted are constant energy contours from double-layer square-net Te planes with A-B stacking. (b) Near $E_F$ M-$\Gamma$-M band dispersion along the dashed diagonal cut in (a) (c) Division of the data in (b) by the Fermi-Dirac function to enhance spectral weight above $E_F$, to highlight the shallow electron-like dispersion origin of the gapped states at the zone center. The dashed line parabola has en effective mass of m*=40. (d) Line spectra at different momenta in (c) also illustrating the electron-like dispersion.
• Figure 4: On-resonant ARPES electronic structure of U 5$f$ states. (a,b) Temperature-dependent on-resonance 98 eV U 5$f$ spectral weight in the two different regions showing similar decoherence behavior. The strong 5$f$ weight at high temperature gives evidence for a high Kondo temperature. Comparison of 10 K and 185 K band dispersions (c,e) and Fermi surface maps (d,f) measured at 60 eV using LH polarization, where the U 5$f$ heavy electron band and light mass Te 5$p$ intensities are comparable allowing their interaction to be probed. The crystal is rotated 45 deg relative to the maps in Fig. 3 and Fig. 4. The T-dependence decoherence of the shallow electron band results in loss of spectral weight relative to the light Te 5$p$ band is observable in the band dispersion image and $E_F$ momentum intensity profile and in the FS map images.
• Figure 5: Tight binding model. (a) Dispersion of the electronic bands near the Fermi energy without the $f$ band, where the horizontal green dashed lines indicate the Fermi energy. (b) The Fermi surface contours for the $p$ bands TB model. Without the $f$ states, the Fermi surface exhibits clear nesting, which favors CDW ordering. (c) The real part of the electronic susceptibility $\chi(q)$ for the $p$ bands TB model, exhibiting a clear peak responsible for CDW. (d, e, f) Similar to (a, b, c) only for the TB model that includes a shallow U $f$ band near the Fermi energy. Here, hybridization between the $f$ and $p$ bands introduces a significant reconstruction of the band structure near the Fermi energy, while the dispersions away from the Fermi level remain largely unchanged. Fermi surface nesting is modified, and the peak in electronic susceptibility is removed.