NbSeTe—a new layered transition metal dichalcogenide superconductor

Abstract

Transition metal dichalcogenides (TMDC's) usually exhibit layered polytypic structures due to the weak interlayer coupling. 2H-NbSe2 is one of the most widely studied in the pristine TMDC family due to its high superconducting transition temperature (Tc = 7.3K) and the occurrence of a charge-density wave (CDW) order below 33 K. The coexistence of CDW with superconductivity poses an intriguing open question about the relationship between Fermi surface nesting and Cooperpairing. Past studies of this issue have mostly been focused on doping 2H-NbSe2 by 3d transition metals without significantly changing its crystal structure. Here we replaced the Se by Te in 2H-NbSe2 in order to design a new 1T polytype layered TMDC NbSeTe, which adopts a trigonal structure with space group P3 ̅ m1. We successfully grew large size and high-quality single crystals of 1T-NbSeTe via the vapor transport method using I2 as the transport agent. Temperature-dependent resistivity and specific heat data revealed a bulk Tc at 1.3 K, which is the first observation of superconductivity in pure 1T-NbSeTe phase. This compound enlarged the family of superconducting TMDC's and provides an opportunity to study the interplay between CDW and superconductivity in the trigonal structure.

Electron–Electron Interaction and Weak Antilocalization Effect in a Transition Metal Dichalcogenide Superconductor

“…At a low temperature of about 3 K, a sharp decrease of the resistivity indicates the superconducting transition, consistent with the previous report on the material. [ 33 ] The zero resistance was not observed here because the lower temperature to millikelvin is not available in the measurement facility. Nevertheless, the bulk superconductivity in the 1T‐NbSeTe has been demonstrated by the previous results, including the zero resistance and the heat capacity characterization.…”

“…The single crystals of 1T‐NbSeTe were grown via the chemical vapor transport method, using I 2 as a transport agent, as reported. [ 33 ] The obtained crystals show a layered structure with metallic silver gray. The composition and the structure of the crystals were investigated by energy‐dispersive x‐ray spectroscopy, scanning electron microscopy, x‐ray diffraction (XRD), and high‐resolution transmission electron microscopy, which reveal that the obtained samples are 1T‐NbSeTe crystallized in the trigonal structure with space group P‐3m1.…”

“…The composition and the structure of the crystals were investigated by energy‐dispersive x‐ray spectroscopy, scanning electron microscopy, x‐ray diffraction (XRD), and high‐resolution transmission electron microscopy, which reveal that the obtained samples are 1T‐NbSeTe crystallized in the trigonal structure with space group P‐3m1. [ 33 ] The composition of three elements is close to 1:1:1 and the Se/Te occupies sites randomly. The inset of Figure a shows the XRD pattern of a typical sample (sample 1, s1), in which the (00n) peaks indicate that the c axis is along the normal direction of the blade‐shaped crystal plane.…”

“…The partial substitution of Se with Te atoms in 2H‐NbSe 2 enables a new TMD superconductor with pure 1T‐NbSeTe phase. [ 33 ] The random occupation of Se/Te sites in the system introduces non‐negligible disorder, making it a promising platform to probe the SOC and disorder in the TMDs through the electron transport study. Here, we experimentally revealed the WAL and EEI in the 1T‐NbSeTe.…”

Investigação ab initio de fases supercondutoras e topológicas em dicalcogenetos de metais de transição

“…Recentemente, um trabalho experimental, em conjunto com cálculos de primeiros princípios, demonstrou que a intercalação de Cu em ZrTe 2 induz supercondutividade nesse sistema, com uma temperatura crítica em torno de 9.7 K (MACHADO et al, 2017) -a maior temperatura crítica observada dentro dos dicalcogenetos de metais de transição supercondutores (YAN et al, 2019). O primeiro tópico de interesse compreende os efeitos multibanda manifestados.…”