# Towards an understanding of hole superconductivity

## TL;DR

This paper explores the fundamental reasons why high-temperature cuprate superconductors and other superconductors are hole superconductors, offering a new understanding of their underlying mechanisms.

## Contribution

It presents a novel perspective on the core reason behind hole superconductivity in cuprates and other superconductors, based on recent insights.

## Key findings

- High Tc cuprates are fundamentally hole superconductors
- The key reason for hole superconductivity has been identified
- All superconductors share the property of being hole superconductors

## Abstract

From the very beginning K. Alex M\"uller emphasized that the materials he and George Bednorz discovered in 1986 were $hole$ superconductors. Here I would like to share with him and others what I believe to be $the$ key reason for why high $T_c$ cuprates as well as all other superconductors are hole superconductors, which I only came to understand a few months ago. This paper is dedicated to Alex M\"uller on the occasion of his 90th birthday.