Ultrastrong Au-Te bonding drives disorder in monolayer ZrTe5 on gold
Abstract
Monolayer ZrTe5 is predicted to host a large-gap quantum spin Hall phase, motivating efforts to isolate single layers of the material. Gold-assisted exfoliation produces clean monolayers of many chalcogen-terminated van der Waals crystals, but the strong Te-Au bond may compete with the bonding network of the ZrTe5 layer itself. Across tens of samples, low-temperature scanning tunneling microscopy on gold-exfoliated flakes shows a disordered monolayer surface in the overwhelming majority of cases, while thicker flakes preserve the characteristic quasi-one-dimensional chain structure. \emph{Ab initio} calculations of the ZrTe5/Au(111) interface reproduce this asymmetry and resolve its mechanism: the Te atoms facing the gold chemisorb, rupturing the weak zigzag Te-Te bonds that cross-link the ZrTe3 chains, turning the discrete bond-length spectrum of the crystal into a continuous one, while the chains persist as distorted units. Charge analysis shows the signature of covalent Te-Au bonding with a modest transfer that hole-dopes the monolayer; in the bilayer, the distortion and the doping stay confined to the layer contacting the gold, and the chemisorption and disorder each preclude the predicted quantum spin Hall phase. The same quasi-covalent Te-Au bond may perturb the contact layer of other gold-exfoliated Te-terminated crystals, particularly those with weakly connected intralayer networks.
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BibTeX
@misc{kandrai2026ultrastrong,
title = {{Ultrastrong Au-Te bonding drives disorder in monolayer ZrTe$_5$ on gold}},
author = {Konrád Kandrai and Zoltán Tajkov and Péter Kun and Levente Tapasztó and János Koltai and Péter Nemes-Incze},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.12836},
eprint = {2609.12836},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.12836},
}
RIS
TY - UNPB
TI - Ultrastrong Au-Te bonding drives disorder in monolayer ZrTe_5 on gold
AU - Konrád Kandrai
AU - Zoltán Tajkov
AU - Péter Kun
AU - Levente Tapasztó
AU - János Koltai
AU - Péter Nemes-Incze
PY - 2026
DA - 2026/09/11
PB - arXiv
DO - 10.48550/arxiv.2609.12836
UR - https://arxiv.org/abs/2609.12836
AB - Monolayer ZrTe_5 is predicted to host a large-gap quantum spin Hall phase, motivating efforts to isolate single layers of the material. Gold-assisted exfoliation produces clean monolayers of many chalcogen-terminated van der Waals crystals, but the strong Te-Au bond may compete with the bonding network of the ZrTe_5 layer itself. Across tens of samples, low-temperature scanning tunneling microscopy on gold-exfoliated flakes shows a disordered monolayer surface in the overwhelming majority of cases, while thicker flakes preserve the characteristic quasi-one-dimensional chain structure. \emph{Ab initio} calculations of the ZrTe_5/Au(111) interface reproduce this asymmetry and resolve its mechanism: the Te atoms facing the gold chemisorb, rupturing the weak zigzag Te-Te bonds that cross-link the ZrTe_3 chains, turning the discrete bond-length spectrum of the crystal into a continuous one, while the chains persist as distorted units. Charge analysis shows the signature of covalent Te-Au bonding with a modest transfer that hole-dopes the monolayer; in the bilayer, the distortion and the doping stay confined to the layer contacting the gold, and the chemisorption and disorder each preclude the predicted quantum spin Hall phase. The same quasi-covalent Te-Au bond may perturb the contact layer of other gold-exfoliated Te-terminated crystals, particularly those with weakly connected intralayer networks.
ER -