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Main Authors: Katayama, Yumiko, Kobayashi, Daiki, Okuma, Hikaru, Yasutake, Yuhsuke, Fukatsu, Susumu, Ueno, Kazunori
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2601.04615
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author Katayama, Yumiko
Kobayashi, Daiki
Okuma, Hikaru
Yasutake, Yuhsuke
Fukatsu, Susumu
Ueno, Kazunori
author_facet Katayama, Yumiko
Kobayashi, Daiki
Okuma, Hikaru
Yasutake, Yuhsuke
Fukatsu, Susumu
Ueno, Kazunori
contents Germanane (GeH) is essentially a hydrogen-terminated Ge analog of graphene with a direct gap (~1.6 eV). Record hole mobility mu_h~67,000 cm2/Vs is found at 15 K for a single allotropic cross-dimensional(D) heterointerface. This is enabled by making topotactically-transformed 2D GeH layers meet the 3D bulk Ge(111). Temperature dependence of mu_h implies metallic conduction without ionized impurity scattering between 20 K and 250 K. Sheet hole density for a Fermi sphere n_S=2.8x10^11 /cm2 agrees well with 3.0x10^11 /cm2 of Hall measurements. A 6,500% magnetoresistance at 7 T accompanies Shubnikov-de Haas oscillations visible even at 15 K. These imply single-band conduction of holes with small effective mass in the in-plane directions, invoking a 2D hole gas (2DHG) picture that allotropic cross-D heterointerface between 2D GeH and 3D Ge harbors 2D-confined high-mobility holes. Even without elaborate heteroepitaxy and modulation doping, allotropic cross-D heterostructures pave the way toward facile 2DHG creation.
format Preprint
id arxiv_https___arxiv_org_abs_2601_04615
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle High mobility holes at germanane/Ge(111) allotropic cross-dimensional heterointerface
Katayama, Yumiko
Kobayashi, Daiki
Okuma, Hikaru
Yasutake, Yuhsuke
Fukatsu, Susumu
Ueno, Kazunori
Materials Science
Germanane (GeH) is essentially a hydrogen-terminated Ge analog of graphene with a direct gap (~1.6 eV). Record hole mobility mu_h~67,000 cm2/Vs is found at 15 K for a single allotropic cross-dimensional(D) heterointerface. This is enabled by making topotactically-transformed 2D GeH layers meet the 3D bulk Ge(111). Temperature dependence of mu_h implies metallic conduction without ionized impurity scattering between 20 K and 250 K. Sheet hole density for a Fermi sphere n_S=2.8x10^11 /cm2 agrees well with 3.0x10^11 /cm2 of Hall measurements. A 6,500% magnetoresistance at 7 T accompanies Shubnikov-de Haas oscillations visible even at 15 K. These imply single-band conduction of holes with small effective mass in the in-plane directions, invoking a 2D hole gas (2DHG) picture that allotropic cross-D heterointerface between 2D GeH and 3D Ge harbors 2D-confined high-mobility holes. Even without elaborate heteroepitaxy and modulation doping, allotropic cross-D heterostructures pave the way toward facile 2DHG creation.
title High mobility holes at germanane/Ge(111) allotropic cross-dimensional heterointerface
topic Materials Science
url https://arxiv.org/abs/2601.04615