WordPress only load after <!–more–> contents using ajax

My wordpress posts structures are like this

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<!--more-->    
Investigationes demonstraverunt<strong> lectores legere</strong> 
me lius quod ii legunt saepius. Claritas est

I shows post content before “more” tag on my home page,
and trying to load after “more” contents separately via ajax,
i wrote some codes but it restuns full post,
but i only need to return after part of “more” tag

ex

Investigationes demonstraverunt<strong> lectores legere</strong> 
    me lius quod ii legunt saepius. Claritas est

only this part my code for get contents via ajax is

<div id="single-post post-<?php the_ID(); ?>">
         <?php while (have_posts()) : the_post(); ?>
                <?php the_content();?>
    <?php endwhile;?>      
    </div>

this give full post anyone know how to get only contents after the “more” tag
Thank You